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linux/arch/arm64/kvm/hyp/sysreg-sr.c

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arm64: KVM: Implement system register save/restore Implement the system register save/restore as a direct translation of the assembly code version. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-19 17:02:48 +00:00
/*
* Copyright (C) 2012-2015 - ARM Ltd
* Author: Marc Zyngier <marc.zyngier@arm.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/compiler.h>
#include <linux/kvm_host.h>
arm64: KVM: Turn system register numbers to an enum Having the system register numbers as #defines has been a pain since day one, as the ordering is pretty fragile, and moving things around leads to renumbering and epic conflict resolutions. Now that we're mostly acessing the sysreg file in C, an enum is a much better type to use, and we can clean things up a bit. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-25 19:57:11 +00:00
#include <asm/kvm_asm.h>
KVM: arm/arm64: Introduce vcpu_el1_is_32bit We have numerous checks around that checks if the HCR_EL2 has the RW bit set to figure out if we're running an AArch64 or AArch32 VM. In some cases, directly checking the RW bit (given its unintuitive name), is a bit confusing, and that's not going to improve as we move logic around for the following patches that optimize KVM on AArch64 hosts with VHE. Therefore, introduce a helper, vcpu_el1_is_32bit, and replace existing direct checks of HCR_EL2.RW with the helper. Reviewed-by: Julien Grall <julien.grall@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-12-13 21:56:48 +00:00
#include <asm/kvm_emulate.h>
arm64: KVM: Move kvm/hyp/hyp.h to include/asm/kvm_hyp.h In order to be able to move code outside of kvm/hyp, we need to make the global hyp.h file accessible from a standard location. include/asm/kvm_hyp.h seems good enough. Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-01-28 13:44:07 +00:00
#include <asm/kvm_hyp.h>
arm64: KVM: Implement system register save/restore Implement the system register save/restore as a direct translation of the assembly code version. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-19 17:02:48 +00:00
arm64: KVM: VHE: Split save/restore of registers shared between guest and host A handful of system registers are still shared between host and guest, even while using VHE (tpidr*_el[01] and actlr_el1). Also, some of the vcpu state (sp_el0, PC and PSTATE) must be save/restored on entry/exit, as they are used on the host as well. In order to facilitate the introduction of a VHE-specific sysreg save/restore, make move the access to these registers to their own save/restore functions. No functional change. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:39:38 +00:00
/*
* Non-VHE: Both host and guest must save everything.
*
KVM: arm64: Defer saving/restoring 64-bit sysregs to vcpu load/put on VHE Some system registers do not affect the host kernel's execution and can therefore be loaded when we are about to run a VCPU and we don't have to restore the host state to the hardware before the time when we are actually about to return to userspace or schedule out the VCPU thread. The EL1 system registers and the userspace state registers only affecting EL0 execution do not need to be saved and restored on every switch between the VM and the host, because they don't affect the host kernel's execution. We mark all registers which are now deffered as such in the vcpu_{read,write}_sys_reg accessors in sys-regs.c to ensure the most up-to-date copy is always accessed. Note MPIDR_EL1 (controlled via VMPIDR_EL2) is accessed from other vcpu threads, for example via the GIC emulation, and therefore must be declared as immediate, which is fine as the guest cannot modify this value. The 32-bit sysregs can also be deferred but we do this in a separate patch as it requires a bit more infrastructure. Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-15 18:43:45 +00:00
* VHE: Host and guest must save mdscr_el1 and sp_el0 (and the PC and pstate,
* which are handled as part of the el2 return state) on every switch.
* tpidr_el0 and tpidrro_el0 only need to be switched when going
* to host userspace or a different VCPU. EL1 registers only need to be
* switched when potentially going to run a different VCPU. The latter two
* classes are handled as part of kvm_arch_vcpu_load and kvm_arch_vcpu_put.
arm64: KVM: VHE: Split save/restore of registers shared between guest and host A handful of system registers are still shared between host and guest, even while using VHE (tpidr*_el[01] and actlr_el1). Also, some of the vcpu state (sp_el0, PC and PSTATE) must be save/restored on entry/exit, as they are used on the host as well. In order to facilitate the introduction of a VHE-specific sysreg save/restore, make move the access to these registers to their own save/restore functions. No functional change. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:39:38 +00:00
*/
static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
{
arm64: KVM: VHE: Context switch MDSCR_EL1 The kprobe enablement work has uncovered that changes made by a guest to MDSCR_EL1 were propagated to the host when VHE was enabled, leading to unexpected exception being delivered. Moving this register to the list of registers that are always context-switched fixes the issue. Fixes: 9c6c35683286 ("arm64: KVM: VHE: Split save/restore of registers shared between guest and host") Cc: stable@vger.kernel.org #4.6 Reported-by: Tirumalesh Chalamarla <Tirumalesh.Chalamarla@cavium.com> Tested-by: Tirumalesh Chalamarla <Tirumalesh.Chalamarla@cavium.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-07-19 12:56:54 +00:00
ctxt->sys_regs[MDSCR_EL1] = read_sysreg(mdscr_el1);
KVM: arm64: Move userspace system registers into separate function There's a semantic difference between the EL1 registers that control operation of a kernel running in EL1 and EL1 registers that only control userspace execution in EL0. Since we can defer saving/restoring the latter, move them into their own function. The ARMv8 ARM (ARM DDI 0487C.a) Section D10.2.1 recommends that ACTLR_EL1 has no effect on the processor when running the VHE host, and we can therefore move this register into the EL1 state which is only saved/restored on vcpu_put/load for a VHE host. We also take this chance to rename the function saving/restoring the remaining system register to make it clear this function deals with the EL1 system registers. Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-15 20:41:55 +00:00
/*
* The host arm64 Linux uses sp_el0 to point to 'current' and it must
* therefore be saved/restored on every entry/exit to/from the guest.
*/
arm64: KVM: VHE: Split save/restore of registers shared between guest and host A handful of system registers are still shared between host and guest, even while using VHE (tpidr*_el[01] and actlr_el1). Also, some of the vcpu state (sp_el0, PC and PSTATE) must be save/restored on entry/exit, as they are used on the host as well. In order to facilitate the introduction of a VHE-specific sysreg save/restore, make move the access to these registers to their own save/restore functions. No functional change. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:39:38 +00:00
ctxt->gp_regs.regs.sp = read_sysreg(sp_el0);
}
KVM: arm64: Move userspace system registers into separate function There's a semantic difference between the EL1 registers that control operation of a kernel running in EL1 and EL1 registers that only control userspace execution in EL0. Since we can defer saving/restoring the latter, move them into their own function. The ARMv8 ARM (ARM DDI 0487C.a) Section D10.2.1 recommends that ACTLR_EL1 has no effect on the processor when running the VHE host, and we can therefore move this register into the EL1 state which is only saved/restored on vcpu_put/load for a VHE host. We also take this chance to rename the function saving/restoring the remaining system register to make it clear this function deals with the EL1 system registers. Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-15 20:41:55 +00:00
static void __hyp_text __sysreg_save_user_state(struct kvm_cpu_context *ctxt)
{
ctxt->sys_regs[TPIDR_EL0] = read_sysreg(tpidr_el0);
ctxt->sys_regs[TPIDRRO_EL0] = read_sysreg(tpidrro_el0);
}
static void __hyp_text __sysreg_save_el1_state(struct kvm_cpu_context *ctxt)
arm64: KVM: Implement system register save/restore Implement the system register save/restore as a direct translation of the assembly code version. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-19 17:02:48 +00:00
{
ctxt->sys_regs[MPIDR_EL1] = read_sysreg(vmpidr_el2);
ctxt->sys_regs[CSSELR_EL1] = read_sysreg(csselr_el1);
arm64: KVM: VHE: Use unified system register accessors Use the recently introduced unified system register accessors for those sysregs that behave differently depending on VHE being in use or not. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:56:25 +00:00
ctxt->sys_regs[SCTLR_EL1] = read_sysreg_el1(sctlr);
KVM: arm64: Move userspace system registers into separate function There's a semantic difference between the EL1 registers that control operation of a kernel running in EL1 and EL1 registers that only control userspace execution in EL0. Since we can defer saving/restoring the latter, move them into their own function. The ARMv8 ARM (ARM DDI 0487C.a) Section D10.2.1 recommends that ACTLR_EL1 has no effect on the processor when running the VHE host, and we can therefore move this register into the EL1 state which is only saved/restored on vcpu_put/load for a VHE host. We also take this chance to rename the function saving/restoring the remaining system register to make it clear this function deals with the EL1 system registers. Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-15 20:41:55 +00:00
ctxt->sys_regs[ACTLR_EL1] = read_sysreg(actlr_el1);
arm64: KVM: VHE: Use unified system register accessors Use the recently introduced unified system register accessors for those sysregs that behave differently depending on VHE being in use or not. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:56:25 +00:00
ctxt->sys_regs[CPACR_EL1] = read_sysreg_el1(cpacr);
ctxt->sys_regs[TTBR0_EL1] = read_sysreg_el1(ttbr0);
ctxt->sys_regs[TTBR1_EL1] = read_sysreg_el1(ttbr1);
ctxt->sys_regs[TCR_EL1] = read_sysreg_el1(tcr);
ctxt->sys_regs[ESR_EL1] = read_sysreg_el1(esr);
ctxt->sys_regs[AFSR0_EL1] = read_sysreg_el1(afsr0);
ctxt->sys_regs[AFSR1_EL1] = read_sysreg_el1(afsr1);
ctxt->sys_regs[FAR_EL1] = read_sysreg_el1(far);
ctxt->sys_regs[MAIR_EL1] = read_sysreg_el1(mair);
ctxt->sys_regs[VBAR_EL1] = read_sysreg_el1(vbar);
ctxt->sys_regs[CONTEXTIDR_EL1] = read_sysreg_el1(contextidr);
ctxt->sys_regs[AMAIR_EL1] = read_sysreg_el1(amair);
ctxt->sys_regs[CNTKCTL_EL1] = read_sysreg_el1(cntkctl);
arm64: KVM: Implement system register save/restore Implement the system register save/restore as a direct translation of the assembly code version. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-19 17:02:48 +00:00
ctxt->sys_regs[PAR_EL1] = read_sysreg(par_el1);
KVM: arm64: Stop save/restoring host tpidr_el1 on VHE Now that a VHE host uses tpidr_el2 for the cpu offset we no longer need KVM to save/restore tpidr_el1. Move this from the 'common' code into the non-vhe code. While we're at it, on VHE we don't need to save the ELR or SPSR as kernel_entry in entry.S will have pushed these onto the kernel stack, and will restore them from there. Move these to the non-vhe code as we need them to get back to the host. Finally remove the always-copy-tpidr we hid in the stage2 setup code, cpufeature's enable callback will do this for VHE, we only need KVM to do it for non-vhe. Add the copy into kvm-init instead. Signed-off-by: James Morse <james.morse@arm.com> Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-01-08 15:38:07 +00:00
ctxt->sys_regs[TPIDR_EL1] = read_sysreg(tpidr_el1);
arm64: KVM: Implement system register save/restore Implement the system register save/restore as a direct translation of the assembly code version. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-19 17:02:48 +00:00
ctxt->gp_regs.sp_el1 = read_sysreg(sp_el1);
arm64: KVM: VHE: Use unified system register accessors Use the recently introduced unified system register accessors for those sysregs that behave differently depending on VHE being in use or not. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:56:25 +00:00
ctxt->gp_regs.elr_el1 = read_sysreg_el1(elr);
ctxt->gp_regs.spsr[KVM_SPSR_EL1]= read_sysreg_el1(spsr);
KVM: arm64: Don't save the host ELR_EL2 and SPSR_EL2 on VHE systems On non-VHE systems we need to save the ELR_EL2 and SPSR_EL2 so that we can return to the host in EL1 in the same state and location where we issued a hypercall to EL2, but on VHE ELR_EL2 and SPSR_EL2 are not useful because we never enter a guest as a result of an exception entry that would be directly handled by KVM. The kernel entry code already saves ELR_EL1/SPSR_EL1 on exception entry, which is enough. Therefore, factor out these registers into separate save/restore functions, making it easy to exclude them from the VHE world-switch path later on. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-10 20:54:57 +00:00
}
static void __hyp_text __sysreg_save_el2_return_state(struct kvm_cpu_context *ctxt)
{
KVM: arm64: Stop save/restoring host tpidr_el1 on VHE Now that a VHE host uses tpidr_el2 for the cpu offset we no longer need KVM to save/restore tpidr_el1. Move this from the 'common' code into the non-vhe code. While we're at it, on VHE we don't need to save the ELR or SPSR as kernel_entry in entry.S will have pushed these onto the kernel stack, and will restore them from there. Move these to the non-vhe code as we need them to get back to the host. Finally remove the always-copy-tpidr we hid in the stage2 setup code, cpufeature's enable callback will do this for VHE, we only need KVM to do it for non-vhe. Add the copy into kvm-init instead. Signed-off-by: James Morse <james.morse@arm.com> Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-01-08 15:38:07 +00:00
ctxt->gp_regs.regs.pc = read_sysreg_el2(elr);
ctxt->gp_regs.regs.pstate = read_sysreg_el2(spsr);
KVM: arm64: Save/Restore guest DISR_EL1 If we deliver a virtual SError to the guest, the guest may defer it with an ESB instruction. The guest reads the deferred value via DISR_EL1, but the guests view of DISR_EL1 is re-mapped to VDISR_EL2 when HCR_EL2.AMO is set. Add the KVM code to save/restore VDISR_EL2, and make it accessible to userspace as DISR_EL1. Signed-off-by: James Morse <james.morse@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-01-15 19:39:02 +00:00
if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN))
ctxt->sys_regs[DISR_EL1] = read_sysreg_s(SYS_VDISR_EL2);
arm64: KVM: Implement system register save/restore Implement the system register save/restore as a direct translation of the assembly code version. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-19 17:02:48 +00:00
}
KVM: arm64: Unify non-VHE host/guest sysreg save and restore functions There is no need to have multiple identical functions with different names for saving host and guest state. When saving and restoring state for the host and guest, the state is the same for both contexts, and that's why we have the kvm_cpu_context structure. Delete one version and rename the other into simply save/restore. Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-10 20:40:13 +00:00
void __hyp_text __sysreg_save_state_nvhe(struct kvm_cpu_context *ctxt)
KVM: arm64: Introduce separate VHE/non-VHE sysreg save/restore functions As we are about to handle system registers quite differently between VHE and non-VHE systems. In preparation for that, we need to split some of the handling functions between VHE and non-VHE functionality. For now, we simply copy the non-VHE functions, but we do change the use of static keys for VHE and non-VHE functionality now that we have separate functions. Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-10 20:19:31 +00:00
{
__sysreg_save_el1_state(ctxt);
__sysreg_save_common_state(ctxt);
__sysreg_save_user_state(ctxt);
KVM: arm64: Don't save the host ELR_EL2 and SPSR_EL2 on VHE systems On non-VHE systems we need to save the ELR_EL2 and SPSR_EL2 so that we can return to the host in EL1 in the same state and location where we issued a hypercall to EL2, but on VHE ELR_EL2 and SPSR_EL2 are not useful because we never enter a guest as a result of an exception entry that would be directly handled by KVM. The kernel entry code already saves ELR_EL1/SPSR_EL1 on exception entry, which is enough. Therefore, factor out these registers into separate save/restore functions, making it easy to exclude them from the VHE world-switch path later on. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-10 20:54:57 +00:00
__sysreg_save_el2_return_state(ctxt);
KVM: arm64: Introduce separate VHE/non-VHE sysreg save/restore functions As we are about to handle system registers quite differently between VHE and non-VHE systems. In preparation for that, we need to split some of the handling functions between VHE and non-VHE functionality. For now, we simply copy the non-VHE functions, but we do change the use of static keys for VHE and non-VHE functionality now that we have separate functions. Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-10 20:19:31 +00:00
}
void sysreg_save_host_state_vhe(struct kvm_cpu_context *ctxt)
arm64: KVM: VHE: Differenciate host/guest sysreg save/restore With ARMv8, host and guest share the same system register file, making the save/restore procedure completely symetrical. With VHE, host and guest now have different requirements, as they use different sysregs. In order to prepare for this, add split sysreg save/restore functions for both host and guest. No functional changes yet. Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:17:35 +00:00
{
arm64: KVM: VHE: Split save/restore of registers shared between guest and host A handful of system registers are still shared between host and guest, even while using VHE (tpidr*_el[01] and actlr_el1). Also, some of the vcpu state (sp_el0, PC and PSTATE) must be save/restored on entry/exit, as they are used on the host as well. In order to facilitate the introduction of a VHE-specific sysreg save/restore, make move the access to these registers to their own save/restore functions. No functional change. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:39:38 +00:00
__sysreg_save_common_state(ctxt);
arm64: KVM: VHE: Differenciate host/guest sysreg save/restore With ARMv8, host and guest share the same system register file, making the save/restore procedure completely symetrical. With VHE, host and guest now have different requirements, as they use different sysregs. In order to prepare for this, add split sysreg save/restore functions for both host and guest. No functional changes yet. Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:17:35 +00:00
}
KVM: arm64: Introduce separate VHE/non-VHE sysreg save/restore functions As we are about to handle system registers quite differently between VHE and non-VHE systems. In preparation for that, we need to split some of the handling functions between VHE and non-VHE functionality. For now, we simply copy the non-VHE functions, but we do change the use of static keys for VHE and non-VHE functionality now that we have separate functions. Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-10 20:19:31 +00:00
void sysreg_save_guest_state_vhe(struct kvm_cpu_context *ctxt)
arm64: KVM: VHE: Differenciate host/guest sysreg save/restore With ARMv8, host and guest share the same system register file, making the save/restore procedure completely symetrical. With VHE, host and guest now have different requirements, as they use different sysregs. In order to prepare for this, add split sysreg save/restore functions for both host and guest. No functional changes yet. Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:17:35 +00:00
{
arm64: KVM: VHE: Split save/restore of registers shared between guest and host A handful of system registers are still shared between host and guest, even while using VHE (tpidr*_el[01] and actlr_el1). Also, some of the vcpu state (sp_el0, PC and PSTATE) must be save/restored on entry/exit, as they are used on the host as well. In order to facilitate the introduction of a VHE-specific sysreg save/restore, make move the access to these registers to their own save/restore functions. No functional change. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:39:38 +00:00
__sysreg_save_common_state(ctxt);
KVM: arm64: Don't save the host ELR_EL2 and SPSR_EL2 on VHE systems On non-VHE systems we need to save the ELR_EL2 and SPSR_EL2 so that we can return to the host in EL1 in the same state and location where we issued a hypercall to EL2, but on VHE ELR_EL2 and SPSR_EL2 are not useful because we never enter a guest as a result of an exception entry that would be directly handled by KVM. The kernel entry code already saves ELR_EL1/SPSR_EL1 on exception entry, which is enough. Therefore, factor out these registers into separate save/restore functions, making it easy to exclude them from the VHE world-switch path later on. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-10 20:54:57 +00:00
__sysreg_save_el2_return_state(ctxt);
arm64: KVM: VHE: Split save/restore of registers shared between guest and host A handful of system registers are still shared between host and guest, even while using VHE (tpidr*_el[01] and actlr_el1). Also, some of the vcpu state (sp_el0, PC and PSTATE) must be save/restored on entry/exit, as they are used on the host as well. In order to facilitate the introduction of a VHE-specific sysreg save/restore, make move the access to these registers to their own save/restore functions. No functional change. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:39:38 +00:00
}
static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctxt)
{
arm64: KVM: VHE: Context switch MDSCR_EL1 The kprobe enablement work has uncovered that changes made by a guest to MDSCR_EL1 were propagated to the host when VHE was enabled, leading to unexpected exception being delivered. Moving this register to the list of registers that are always context-switched fixes the issue. Fixes: 9c6c35683286 ("arm64: KVM: VHE: Split save/restore of registers shared between guest and host") Cc: stable@vger.kernel.org #4.6 Reported-by: Tirumalesh Chalamarla <Tirumalesh.Chalamarla@cavium.com> Tested-by: Tirumalesh Chalamarla <Tirumalesh.Chalamarla@cavium.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-07-19 12:56:54 +00:00
write_sysreg(ctxt->sys_regs[MDSCR_EL1], mdscr_el1);
KVM: arm64: Move userspace system registers into separate function There's a semantic difference between the EL1 registers that control operation of a kernel running in EL1 and EL1 registers that only control userspace execution in EL0. Since we can defer saving/restoring the latter, move them into their own function. The ARMv8 ARM (ARM DDI 0487C.a) Section D10.2.1 recommends that ACTLR_EL1 has no effect on the processor when running the VHE host, and we can therefore move this register into the EL1 state which is only saved/restored on vcpu_put/load for a VHE host. We also take this chance to rename the function saving/restoring the remaining system register to make it clear this function deals with the EL1 system registers. Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-15 20:41:55 +00:00
/*
* The host arm64 Linux uses sp_el0 to point to 'current' and it must
* therefore be saved/restored on every entry/exit to/from the guest.
*/
arm64: KVM: VHE: Split save/restore of registers shared between guest and host A handful of system registers are still shared between host and guest, even while using VHE (tpidr*_el[01] and actlr_el1). Also, some of the vcpu state (sp_el0, PC and PSTATE) must be save/restored on entry/exit, as they are used on the host as well. In order to facilitate the introduction of a VHE-specific sysreg save/restore, make move the access to these registers to their own save/restore functions. No functional change. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:39:38 +00:00
write_sysreg(ctxt->gp_regs.regs.sp, sp_el0);
arm64: KVM: VHE: Differenciate host/guest sysreg save/restore With ARMv8, host and guest share the same system register file, making the save/restore procedure completely symetrical. With VHE, host and guest now have different requirements, as they use different sysregs. In order to prepare for this, add split sysreg save/restore functions for both host and guest. No functional changes yet. Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:17:35 +00:00
}
KVM: arm64: Move userspace system registers into separate function There's a semantic difference between the EL1 registers that control operation of a kernel running in EL1 and EL1 registers that only control userspace execution in EL0. Since we can defer saving/restoring the latter, move them into their own function. The ARMv8 ARM (ARM DDI 0487C.a) Section D10.2.1 recommends that ACTLR_EL1 has no effect on the processor when running the VHE host, and we can therefore move this register into the EL1 state which is only saved/restored on vcpu_put/load for a VHE host. We also take this chance to rename the function saving/restoring the remaining system register to make it clear this function deals with the EL1 system registers. Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-15 20:41:55 +00:00
static void __hyp_text __sysreg_restore_user_state(struct kvm_cpu_context *ctxt)
{
write_sysreg(ctxt->sys_regs[TPIDR_EL0], tpidr_el0);
write_sysreg(ctxt->sys_regs[TPIDRRO_EL0], tpidrro_el0);
}
static void __hyp_text __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt)
arm64: KVM: Implement system register save/restore Implement the system register save/restore as a direct translation of the assembly code version. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-19 17:02:48 +00:00
{
arm64: KVM: VHE: Use unified system register accessors Use the recently introduced unified system register accessors for those sysregs that behave differently depending on VHE being in use or not. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:56:25 +00:00
write_sysreg(ctxt->sys_regs[MPIDR_EL1], vmpidr_el2);
write_sysreg(ctxt->sys_regs[CSSELR_EL1], csselr_el1);
write_sysreg_el1(ctxt->sys_regs[SCTLR_EL1], sctlr);
KVM: arm64: Move userspace system registers into separate function There's a semantic difference between the EL1 registers that control operation of a kernel running in EL1 and EL1 registers that only control userspace execution in EL0. Since we can defer saving/restoring the latter, move them into their own function. The ARMv8 ARM (ARM DDI 0487C.a) Section D10.2.1 recommends that ACTLR_EL1 has no effect on the processor when running the VHE host, and we can therefore move this register into the EL1 state which is only saved/restored on vcpu_put/load for a VHE host. We also take this chance to rename the function saving/restoring the remaining system register to make it clear this function deals with the EL1 system registers. Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-15 20:41:55 +00:00
write_sysreg(ctxt->sys_regs[ACTLR_EL1], actlr_el1);
arm64: KVM: VHE: Use unified system register accessors Use the recently introduced unified system register accessors for those sysregs that behave differently depending on VHE being in use or not. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:56:25 +00:00
write_sysreg_el1(ctxt->sys_regs[CPACR_EL1], cpacr);
write_sysreg_el1(ctxt->sys_regs[TTBR0_EL1], ttbr0);
write_sysreg_el1(ctxt->sys_regs[TTBR1_EL1], ttbr1);
write_sysreg_el1(ctxt->sys_regs[TCR_EL1], tcr);
write_sysreg_el1(ctxt->sys_regs[ESR_EL1], esr);
write_sysreg_el1(ctxt->sys_regs[AFSR0_EL1], afsr0);
write_sysreg_el1(ctxt->sys_regs[AFSR1_EL1], afsr1);
write_sysreg_el1(ctxt->sys_regs[FAR_EL1], far);
write_sysreg_el1(ctxt->sys_regs[MAIR_EL1], mair);
write_sysreg_el1(ctxt->sys_regs[VBAR_EL1], vbar);
write_sysreg_el1(ctxt->sys_regs[CONTEXTIDR_EL1],contextidr);
write_sysreg_el1(ctxt->sys_regs[AMAIR_EL1], amair);
write_sysreg_el1(ctxt->sys_regs[CNTKCTL_EL1], cntkctl);
write_sysreg(ctxt->sys_regs[PAR_EL1], par_el1);
KVM: arm64: Stop save/restoring host tpidr_el1 on VHE Now that a VHE host uses tpidr_el2 for the cpu offset we no longer need KVM to save/restore tpidr_el1. Move this from the 'common' code into the non-vhe code. While we're at it, on VHE we don't need to save the ELR or SPSR as kernel_entry in entry.S will have pushed these onto the kernel stack, and will restore them from there. Move these to the non-vhe code as we need them to get back to the host. Finally remove the always-copy-tpidr we hid in the stage2 setup code, cpufeature's enable callback will do this for VHE, we only need KVM to do it for non-vhe. Add the copy into kvm-init instead. Signed-off-by: James Morse <james.morse@arm.com> Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-01-08 15:38:07 +00:00
write_sysreg(ctxt->sys_regs[TPIDR_EL1], tpidr_el1);
arm64: KVM: VHE: Use unified system register accessors Use the recently introduced unified system register accessors for those sysregs that behave differently depending on VHE being in use or not. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:56:25 +00:00
write_sysreg(ctxt->gp_regs.sp_el1, sp_el1);
write_sysreg_el1(ctxt->gp_regs.elr_el1, elr);
write_sysreg_el1(ctxt->gp_regs.spsr[KVM_SPSR_EL1],spsr);
KVM: arm64: Don't save the host ELR_EL2 and SPSR_EL2 on VHE systems On non-VHE systems we need to save the ELR_EL2 and SPSR_EL2 so that we can return to the host in EL1 in the same state and location where we issued a hypercall to EL2, but on VHE ELR_EL2 and SPSR_EL2 are not useful because we never enter a guest as a result of an exception entry that would be directly handled by KVM. The kernel entry code already saves ELR_EL1/SPSR_EL1 on exception entry, which is enough. Therefore, factor out these registers into separate save/restore functions, making it easy to exclude them from the VHE world-switch path later on. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-10 20:54:57 +00:00
}
static void __hyp_text
__sysreg_restore_el2_return_state(struct kvm_cpu_context *ctxt)
{
KVM: arm64: Stop save/restoring host tpidr_el1 on VHE Now that a VHE host uses tpidr_el2 for the cpu offset we no longer need KVM to save/restore tpidr_el1. Move this from the 'common' code into the non-vhe code. While we're at it, on VHE we don't need to save the ELR or SPSR as kernel_entry in entry.S will have pushed these onto the kernel stack, and will restore them from there. Move these to the non-vhe code as we need them to get back to the host. Finally remove the always-copy-tpidr we hid in the stage2 setup code, cpufeature's enable callback will do this for VHE, we only need KVM to do it for non-vhe. Add the copy into kvm-init instead. Signed-off-by: James Morse <james.morse@arm.com> Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-01-08 15:38:07 +00:00
write_sysreg_el2(ctxt->gp_regs.regs.pc, elr);
write_sysreg_el2(ctxt->gp_regs.regs.pstate, spsr);
KVM: arm64: Save/Restore guest DISR_EL1 If we deliver a virtual SError to the guest, the guest may defer it with an ESB instruction. The guest reads the deferred value via DISR_EL1, but the guests view of DISR_EL1 is re-mapped to VDISR_EL2 when HCR_EL2.AMO is set. Add the KVM code to save/restore VDISR_EL2, and make it accessible to userspace as DISR_EL1. Signed-off-by: James Morse <james.morse@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-01-15 19:39:02 +00:00
if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN))
write_sysreg_s(ctxt->sys_regs[DISR_EL1], SYS_VDISR_EL2);
arm64: KVM: Implement system register save/restore Implement the system register save/restore as a direct translation of the assembly code version. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-19 17:02:48 +00:00
}
arm64: KVM: Implement 32bit system register save/restore Implement the 32bit system register save/restore as a direct translation of the assembly code version. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-19 18:28:29 +00:00
KVM: arm64: Unify non-VHE host/guest sysreg save and restore functions There is no need to have multiple identical functions with different names for saving host and guest state. When saving and restoring state for the host and guest, the state is the same for both contexts, and that's why we have the kvm_cpu_context structure. Delete one version and rename the other into simply save/restore. Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-10 20:40:13 +00:00
void __hyp_text __sysreg_restore_state_nvhe(struct kvm_cpu_context *ctxt)
KVM: arm64: Introduce separate VHE/non-VHE sysreg save/restore functions As we are about to handle system registers quite differently between VHE and non-VHE systems. In preparation for that, we need to split some of the handling functions between VHE and non-VHE functionality. For now, we simply copy the non-VHE functions, but we do change the use of static keys for VHE and non-VHE functionality now that we have separate functions. Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-10 20:19:31 +00:00
{
__sysreg_restore_el1_state(ctxt);
__sysreg_restore_common_state(ctxt);
__sysreg_restore_user_state(ctxt);
KVM: arm64: Don't save the host ELR_EL2 and SPSR_EL2 on VHE systems On non-VHE systems we need to save the ELR_EL2 and SPSR_EL2 so that we can return to the host in EL1 in the same state and location where we issued a hypercall to EL2, but on VHE ELR_EL2 and SPSR_EL2 are not useful because we never enter a guest as a result of an exception entry that would be directly handled by KVM. The kernel entry code already saves ELR_EL1/SPSR_EL1 on exception entry, which is enough. Therefore, factor out these registers into separate save/restore functions, making it easy to exclude them from the VHE world-switch path later on. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-10 20:54:57 +00:00
__sysreg_restore_el2_return_state(ctxt);
KVM: arm64: Introduce separate VHE/non-VHE sysreg save/restore functions As we are about to handle system registers quite differently between VHE and non-VHE systems. In preparation for that, we need to split some of the handling functions between VHE and non-VHE functionality. For now, we simply copy the non-VHE functions, but we do change the use of static keys for VHE and non-VHE functionality now that we have separate functions. Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-10 20:19:31 +00:00
}
void sysreg_restore_host_state_vhe(struct kvm_cpu_context *ctxt)
arm64: KVM: VHE: Differenciate host/guest sysreg save/restore With ARMv8, host and guest share the same system register file, making the save/restore procedure completely symetrical. With VHE, host and guest now have different requirements, as they use different sysregs. In order to prepare for this, add split sysreg save/restore functions for both host and guest. No functional changes yet. Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:17:35 +00:00
{
arm64: KVM: VHE: Split save/restore of registers shared between guest and host A handful of system registers are still shared between host and guest, even while using VHE (tpidr*_el[01] and actlr_el1). Also, some of the vcpu state (sp_el0, PC and PSTATE) must be save/restored on entry/exit, as they are used on the host as well. In order to facilitate the introduction of a VHE-specific sysreg save/restore, make move the access to these registers to their own save/restore functions. No functional change. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:39:38 +00:00
__sysreg_restore_common_state(ctxt);
arm64: KVM: VHE: Differenciate host/guest sysreg save/restore With ARMv8, host and guest share the same system register file, making the save/restore procedure completely symetrical. With VHE, host and guest now have different requirements, as they use different sysregs. In order to prepare for this, add split sysreg save/restore functions for both host and guest. No functional changes yet. Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:17:35 +00:00
}
KVM: arm64: Introduce separate VHE/non-VHE sysreg save/restore functions As we are about to handle system registers quite differently between VHE and non-VHE systems. In preparation for that, we need to split some of the handling functions between VHE and non-VHE functionality. For now, we simply copy the non-VHE functions, but we do change the use of static keys for VHE and non-VHE functionality now that we have separate functions. Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-10 20:19:31 +00:00
void sysreg_restore_guest_state_vhe(struct kvm_cpu_context *ctxt)
arm64: KVM: VHE: Differenciate host/guest sysreg save/restore With ARMv8, host and guest share the same system register file, making the save/restore procedure completely symetrical. With VHE, host and guest now have different requirements, as they use different sysregs. In order to prepare for this, add split sysreg save/restore functions for both host and guest. No functional changes yet. Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:17:35 +00:00
{
arm64: KVM: VHE: Split save/restore of registers shared between guest and host A handful of system registers are still shared between host and guest, even while using VHE (tpidr*_el[01] and actlr_el1). Also, some of the vcpu state (sp_el0, PC and PSTATE) must be save/restored on entry/exit, as they are used on the host as well. In order to facilitate the introduction of a VHE-specific sysreg save/restore, make move the access to these registers to their own save/restore functions. No functional change. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:39:38 +00:00
__sysreg_restore_common_state(ctxt);
KVM: arm64: Don't save the host ELR_EL2 and SPSR_EL2 on VHE systems On non-VHE systems we need to save the ELR_EL2 and SPSR_EL2 so that we can return to the host in EL1 in the same state and location where we issued a hypercall to EL2, but on VHE ELR_EL2 and SPSR_EL2 are not useful because we never enter a guest as a result of an exception entry that would be directly handled by KVM. The kernel entry code already saves ELR_EL1/SPSR_EL1 on exception entry, which is enough. Therefore, factor out these registers into separate save/restore functions, making it easy to exclude them from the VHE world-switch path later on. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-10 20:54:57 +00:00
__sysreg_restore_el2_return_state(ctxt);
arm64: KVM: VHE: Differenciate host/guest sysreg save/restore With ARMv8, host and guest share the same system register file, making the save/restore procedure completely symetrical. With VHE, host and guest now have different requirements, as they use different sysregs. In order to prepare for this, add split sysreg save/restore functions for both host and guest. No functional changes yet. Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-28 12:17:35 +00:00
}
arm64: KVM: Implement 32bit system register save/restore Implement the 32bit system register save/restore as a direct translation of the assembly code version. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-19 18:28:29 +00:00
void __hyp_text __sysreg32_save_state(struct kvm_vcpu *vcpu)
{
u64 *spsr, *sysreg;
KVM: arm/arm64: Introduce vcpu_el1_is_32bit We have numerous checks around that checks if the HCR_EL2 has the RW bit set to figure out if we're running an AArch64 or AArch32 VM. In some cases, directly checking the RW bit (given its unintuitive name), is a bit confusing, and that's not going to improve as we move logic around for the following patches that optimize KVM on AArch64 hosts with VHE. Therefore, introduce a helper, vcpu_el1_is_32bit, and replace existing direct checks of HCR_EL2.RW with the helper. Reviewed-by: Julien Grall <julien.grall@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-12-13 21:56:48 +00:00
if (!vcpu_el1_is_32bit(vcpu))
arm64: KVM: Implement 32bit system register save/restore Implement the 32bit system register save/restore as a direct translation of the assembly code version. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-19 18:28:29 +00:00
return;
spsr = vcpu->arch.ctxt.gp_regs.spsr;
sysreg = vcpu->arch.ctxt.sys_regs;
spsr[KVM_SPSR_ABT] = read_sysreg(spsr_abt);
spsr[KVM_SPSR_UND] = read_sysreg(spsr_und);
spsr[KVM_SPSR_IRQ] = read_sysreg(spsr_irq);
spsr[KVM_SPSR_FIQ] = read_sysreg(spsr_fiq);
sysreg[DACR32_EL2] = read_sysreg(dacr32_el2);
sysreg[IFSR32_EL2] = read_sysreg(ifsr32_el2);
KVM: arm64: Repurpose vcpu_arch.debug_flags for general-purpose flags In struct vcpu_arch, the debug_flags field is used to store debug-related flags about the vcpu state. Since we are about to add some more flags related to FPSIMD and SVE, it makes sense to add them to the existing flags field rather than adding new fields. Since there is only one debug_flags flag defined so far, there is plenty of free space for expansion. In preparation for adding more flags, this patch renames the debug_flags field to simply "flags", and updates comments appropriately. The flag definitions are also moved to <asm/kvm_host.h>, since their presence in <asm/kvm_asm.h> was for purely historical reasons: these definitions are not used from asm any more, and not very likely to be as more Hyp asm is migrated to C. KVM_ARM64_DEBUG_DIRTY_SHIFT has not been used since commit 1ea66d27e7b0 ("arm64: KVM: Move away from the assembly version of the world switch"), so this patch gets rid of that too. No functional change. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Acked-by: Christoffer Dall <christoffer.dall@arm.com> [maz: fixed minor conflict] Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2018-05-08 13:47:23 +00:00
if (has_vhe() || vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY)
arm64: KVM: Implement 32bit system register save/restore Implement the 32bit system register save/restore as a direct translation of the assembly code version. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-19 18:28:29 +00:00
sysreg[DBGVCR32_EL2] = read_sysreg(dbgvcr32_el2);
}
void __hyp_text __sysreg32_restore_state(struct kvm_vcpu *vcpu)
{
u64 *spsr, *sysreg;
KVM: arm/arm64: Introduce vcpu_el1_is_32bit We have numerous checks around that checks if the HCR_EL2 has the RW bit set to figure out if we're running an AArch64 or AArch32 VM. In some cases, directly checking the RW bit (given its unintuitive name), is a bit confusing, and that's not going to improve as we move logic around for the following patches that optimize KVM on AArch64 hosts with VHE. Therefore, introduce a helper, vcpu_el1_is_32bit, and replace existing direct checks of HCR_EL2.RW with the helper. Reviewed-by: Julien Grall <julien.grall@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-12-13 21:56:48 +00:00
if (!vcpu_el1_is_32bit(vcpu))
arm64: KVM: Implement 32bit system register save/restore Implement the 32bit system register save/restore as a direct translation of the assembly code version. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-19 18:28:29 +00:00
return;
spsr = vcpu->arch.ctxt.gp_regs.spsr;
sysreg = vcpu->arch.ctxt.sys_regs;
write_sysreg(spsr[KVM_SPSR_ABT], spsr_abt);
write_sysreg(spsr[KVM_SPSR_UND], spsr_und);
write_sysreg(spsr[KVM_SPSR_IRQ], spsr_irq);
write_sysreg(spsr[KVM_SPSR_FIQ], spsr_fiq);
write_sysreg(sysreg[DACR32_EL2], dacr32_el2);
write_sysreg(sysreg[IFSR32_EL2], ifsr32_el2);
KVM: arm64: Repurpose vcpu_arch.debug_flags for general-purpose flags In struct vcpu_arch, the debug_flags field is used to store debug-related flags about the vcpu state. Since we are about to add some more flags related to FPSIMD and SVE, it makes sense to add them to the existing flags field rather than adding new fields. Since there is only one debug_flags flag defined so far, there is plenty of free space for expansion. In preparation for adding more flags, this patch renames the debug_flags field to simply "flags", and updates comments appropriately. The flag definitions are also moved to <asm/kvm_host.h>, since their presence in <asm/kvm_asm.h> was for purely historical reasons: these definitions are not used from asm any more, and not very likely to be as more Hyp asm is migrated to C. KVM_ARM64_DEBUG_DIRTY_SHIFT has not been used since commit 1ea66d27e7b0 ("arm64: KVM: Move away from the assembly version of the world switch"), so this patch gets rid of that too. No functional change. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Acked-by: Christoffer Dall <christoffer.dall@arm.com> [maz: fixed minor conflict] Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2018-05-08 13:47:23 +00:00
if (has_vhe() || vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY)
arm64: KVM: Implement 32bit system register save/restore Implement the 32bit system register save/restore as a direct translation of the assembly code version. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-19 18:28:29 +00:00
write_sysreg(sysreg[DBGVCR32_EL2], dbgvcr32_el2);
}
KVM: arm64: Avoid storing the vcpu pointer on the stack We already have the percpu area for the host cpu state, which points to the VCPU, so there's no need to store the VCPU pointer on the stack on every context switch. We can be a little more clever and just use tpidr_el2 for the percpu offset and load the VCPU pointer from the host context. This has the benefit of being able to retrieve the host context even when our stack is corrupted, and it has a potential performance benefit because we trade a store plus a load for an mrs and a load on a round trip to the guest. This does require us to calculate the percpu offset without including the offset from the kernel mapping of the percpu array to the linear mapping of the array (which is what we store in tpidr_el1), because a PC-relative generated address in EL2 is already giving us the hyp alias of the linear mapping of a kernel address. We do this in __cpu_init_hyp_mode() by using kvm_ksym_ref(). The code that accesses ESR_EL2 was previously using an alternative to use the _EL1 accessor on VHE systems, but this was actually unnecessary as the _EL1 accessor aliases the ESR_EL2 register on VHE, and the _EL2 accessor does the same thing on both systems. Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-08 15:01:56 +00:00
KVM: arm/arm64: Add kvm_vcpu_load_sysregs and kvm_vcpu_put_sysregs As we are about to move a bunch of save/restore logic for VHE kernels to the load and put functions, we need some infrastructure to do this. Reviewed-by: Andrew Jones <drjones@redhat.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-10 08:21:18 +00:00
/**
* kvm_vcpu_load_sysregs - Load guest system registers to the physical CPU
*
* @vcpu: The VCPU pointer
*
* Load system registers that do not affect the host's execution, for
* example EL1 system registers on a VHE system where the host kernel
* runs at EL2. This function is called from KVM's vcpu_load() function
* and loading system register state early avoids having to load them on
* every entry to the VM.
*/
void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu)
{
KVM: arm64: Defer saving/restoring 64-bit sysregs to vcpu load/put on VHE Some system registers do not affect the host kernel's execution and can therefore be loaded when we are about to run a VCPU and we don't have to restore the host state to the hardware before the time when we are actually about to return to userspace or schedule out the VCPU thread. The EL1 system registers and the userspace state registers only affecting EL0 execution do not need to be saved and restored on every switch between the VM and the host, because they don't affect the host kernel's execution. We mark all registers which are now deffered as such in the vcpu_{read,write}_sys_reg accessors in sys-regs.c to ensure the most up-to-date copy is always accessed. Note MPIDR_EL1 (controlled via VMPIDR_EL2) is accessed from other vcpu threads, for example via the GIC emulation, and therefore must be declared as immediate, which is fine as the guest cannot modify this value. The 32-bit sysregs can also be deferred but we do this in a separate patch as it requires a bit more infrastructure. Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-15 18:43:45 +00:00
struct kvm_cpu_context *host_ctxt = vcpu->arch.host_cpu_context;
struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt;
if (!has_vhe())
return;
__sysreg_save_user_state(host_ctxt);
KVM: arm64: Defer saving/restoring 32-bit sysregs to vcpu load/put When running a 32-bit VM (EL1 in AArch32), the AArch32 system registers can be deferred to vcpu load/put on VHE systems because neither the host kernel nor host userspace uses these registers. Note that we can't save DBGVCR32_EL2 conditionally based on the state of the debug dirty flag on VHE after this change, because during vcpu_load() we haven't calculated a valid debug flag yet, and when we've restored the register during vcpu_load() we also have to save it during vcpu_put(). This means that we'll always restore/save the register for VHE on load/put, but luckily vcpu load/put are called rarely, so saving an extra register unconditionally shouldn't significantly hurt performance. We can also not defer saving FPEXC32_32 because this register only holds a guest-valid value for 32-bit guests during the exit path when the guest has used FPSIMD registers and restored the register in the early assembly handler from taking the EL2 fault, and therefore we have to check if fpsimd is enabled for the guest in the exit path and save the register then, for both VHE and non-VHE guests. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-12-27 21:12:12 +00:00
/*
* Load guest EL1 and user state
*
* We must restore the 32-bit state before the sysregs, thanks
* to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
*/
__sysreg32_restore_state(vcpu);
KVM: arm64: Defer saving/restoring 64-bit sysregs to vcpu load/put on VHE Some system registers do not affect the host kernel's execution and can therefore be loaded when we are about to run a VCPU and we don't have to restore the host state to the hardware before the time when we are actually about to return to userspace or schedule out the VCPU thread. The EL1 system registers and the userspace state registers only affecting EL0 execution do not need to be saved and restored on every switch between the VM and the host, because they don't affect the host kernel's execution. We mark all registers which are now deffered as such in the vcpu_{read,write}_sys_reg accessors in sys-regs.c to ensure the most up-to-date copy is always accessed. Note MPIDR_EL1 (controlled via VMPIDR_EL2) is accessed from other vcpu threads, for example via the GIC emulation, and therefore must be declared as immediate, which is fine as the guest cannot modify this value. The 32-bit sysregs can also be deferred but we do this in a separate patch as it requires a bit more infrastructure. Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-15 18:43:45 +00:00
__sysreg_restore_user_state(guest_ctxt);
__sysreg_restore_el1_state(guest_ctxt);
vcpu->arch.sysregs_loaded_on_cpu = true;
KVM: arm64: Configure c15, PMU, and debug register traps on cpu load/put for VHE We do not have to change the c15 trap setting on each switch to/from the guest on VHE systems, because this setting only affects guest EL1/EL0 (and therefore not the VHE host). The PMU and debug trap configuration can also be done on vcpu load/put instead, because they don't affect how the VHE host kernel can access the debug registers while executing KVM kernel code. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-08-04 11:47:18 +00:00
activate_traps_vhe_load(vcpu);
KVM: arm/arm64: Add kvm_vcpu_load_sysregs and kvm_vcpu_put_sysregs As we are about to move a bunch of save/restore logic for VHE kernels to the load and put functions, we need some infrastructure to do this. Reviewed-by: Andrew Jones <drjones@redhat.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-10 08:21:18 +00:00
}
/**
* kvm_vcpu_put_sysregs - Restore host system registers to the physical CPU
*
* @vcpu: The VCPU pointer
*
* Save guest system registers that do not affect the host's execution, for
* example EL1 system registers on a VHE system where the host kernel
* runs at EL2. This function is called from KVM's vcpu_put() function
* and deferring saving system register state until we're no longer running the
* VCPU avoids having to save them on every exit from the VM.
*/
void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu)
{
KVM: arm64: Defer saving/restoring 64-bit sysregs to vcpu load/put on VHE Some system registers do not affect the host kernel's execution and can therefore be loaded when we are about to run a VCPU and we don't have to restore the host state to the hardware before the time when we are actually about to return to userspace or schedule out the VCPU thread. The EL1 system registers and the userspace state registers only affecting EL0 execution do not need to be saved and restored on every switch between the VM and the host, because they don't affect the host kernel's execution. We mark all registers which are now deffered as such in the vcpu_{read,write}_sys_reg accessors in sys-regs.c to ensure the most up-to-date copy is always accessed. Note MPIDR_EL1 (controlled via VMPIDR_EL2) is accessed from other vcpu threads, for example via the GIC emulation, and therefore must be declared as immediate, which is fine as the guest cannot modify this value. The 32-bit sysregs can also be deferred but we do this in a separate patch as it requires a bit more infrastructure. Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-15 18:43:45 +00:00
struct kvm_cpu_context *host_ctxt = vcpu->arch.host_cpu_context;
struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt;
if (!has_vhe())
return;
KVM: arm64: Configure c15, PMU, and debug register traps on cpu load/put for VHE We do not have to change the c15 trap setting on each switch to/from the guest on VHE systems, because this setting only affects guest EL1/EL0 (and therefore not the VHE host). The PMU and debug trap configuration can also be done on vcpu load/put instead, because they don't affect how the VHE host kernel can access the debug registers while executing KVM kernel code. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-08-04 11:47:18 +00:00
deactivate_traps_vhe_put();
KVM: arm64: Defer saving/restoring 64-bit sysregs to vcpu load/put on VHE Some system registers do not affect the host kernel's execution and can therefore be loaded when we are about to run a VCPU and we don't have to restore the host state to the hardware before the time when we are actually about to return to userspace or schedule out the VCPU thread. The EL1 system registers and the userspace state registers only affecting EL0 execution do not need to be saved and restored on every switch between the VM and the host, because they don't affect the host kernel's execution. We mark all registers which are now deffered as such in the vcpu_{read,write}_sys_reg accessors in sys-regs.c to ensure the most up-to-date copy is always accessed. Note MPIDR_EL1 (controlled via VMPIDR_EL2) is accessed from other vcpu threads, for example via the GIC emulation, and therefore must be declared as immediate, which is fine as the guest cannot modify this value. The 32-bit sysregs can also be deferred but we do this in a separate patch as it requires a bit more infrastructure. Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-15 18:43:45 +00:00
__sysreg_save_el1_state(guest_ctxt);
__sysreg_save_user_state(guest_ctxt);
KVM: arm64: Defer saving/restoring 32-bit sysregs to vcpu load/put When running a 32-bit VM (EL1 in AArch32), the AArch32 system registers can be deferred to vcpu load/put on VHE systems because neither the host kernel nor host userspace uses these registers. Note that we can't save DBGVCR32_EL2 conditionally based on the state of the debug dirty flag on VHE after this change, because during vcpu_load() we haven't calculated a valid debug flag yet, and when we've restored the register during vcpu_load() we also have to save it during vcpu_put(). This means that we'll always restore/save the register for VHE on load/put, but luckily vcpu load/put are called rarely, so saving an extra register unconditionally shouldn't significantly hurt performance. We can also not defer saving FPEXC32_32 because this register only holds a guest-valid value for 32-bit guests during the exit path when the guest has used FPSIMD registers and restored the register in the early assembly handler from taking the EL2 fault, and therefore we have to check if fpsimd is enabled for the guest in the exit path and save the register then, for both VHE and non-VHE guests. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-12-27 21:12:12 +00:00
__sysreg32_save_state(vcpu);
KVM: arm64: Defer saving/restoring 64-bit sysregs to vcpu load/put on VHE Some system registers do not affect the host kernel's execution and can therefore be loaded when we are about to run a VCPU and we don't have to restore the host state to the hardware before the time when we are actually about to return to userspace or schedule out the VCPU thread. The EL1 system registers and the userspace state registers only affecting EL0 execution do not need to be saved and restored on every switch between the VM and the host, because they don't affect the host kernel's execution. We mark all registers which are now deffered as such in the vcpu_{read,write}_sys_reg accessors in sys-regs.c to ensure the most up-to-date copy is always accessed. Note MPIDR_EL1 (controlled via VMPIDR_EL2) is accessed from other vcpu threads, for example via the GIC emulation, and therefore must be declared as immediate, which is fine as the guest cannot modify this value. The 32-bit sysregs can also be deferred but we do this in a separate patch as it requires a bit more infrastructure. Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-03-15 18:43:45 +00:00
/* Restore host user state */
__sysreg_restore_user_state(host_ctxt);
vcpu->arch.sysregs_loaded_on_cpu = false;
KVM: arm/arm64: Add kvm_vcpu_load_sysregs and kvm_vcpu_put_sysregs As we are about to move a bunch of save/restore logic for VHE kernels to the load and put functions, we need some infrastructure to do this. Reviewed-by: Andrew Jones <drjones@redhat.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-10 08:21:18 +00:00
}
KVM: arm64: Avoid storing the vcpu pointer on the stack We already have the percpu area for the host cpu state, which points to the VCPU, so there's no need to store the VCPU pointer on the stack on every context switch. We can be a little more clever and just use tpidr_el2 for the percpu offset and load the VCPU pointer from the host context. This has the benefit of being able to retrieve the host context even when our stack is corrupted, and it has a potential performance benefit because we trade a store plus a load for an mrs and a load on a round trip to the guest. This does require us to calculate the percpu offset without including the offset from the kernel mapping of the percpu array to the linear mapping of the array (which is what we store in tpidr_el1), because a PC-relative generated address in EL2 is already giving us the hyp alias of the linear mapping of a kernel address. We do this in __cpu_init_hyp_mode() by using kvm_ksym_ref(). The code that accesses ESR_EL2 was previously using an alternative to use the _EL1 accessor on VHE systems, but this was actually unnecessary as the _EL1 accessor aliases the ESR_EL2 register on VHE, and the _EL2 accessor does the same thing on both systems. Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-10-08 15:01:56 +00:00
void __hyp_text __kvm_set_tpidr_el2(u64 tpidr_el2)
{
asm("msr tpidr_el2, %0": : "r" (tpidr_el2));
}
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