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KVM/arm64 fixes for 5.16, take #2

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- Fix constant sign extension affecting TCR_EL2 and preventing
   running on ARMv8.7 models due to spurious bits being set
 
 - Fix use of helpers using PSTATE early on exit by always sampling
   it as soon as the exit takes place
 
 - Move pkvm's 32bit handling into a common helper
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Merge tag 'kvmarm-fixes-5.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 5.16, take #2

- Fix constant sign extension affecting TCR_EL2 and preventing
  running on ARMv8.7 models due to spurious bits being set

- Fix use of helpers using PSTATE early on exit by always sampling
  it as soon as the exit takes place

- Move pkvm's 32bit handling into a common helper
This commit is contained in:
Paolo Bonzini 2021-11-26 05:42:56 -05:00
commit 3d627cc30d
5 changed files with 27 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/arm64/include/asm/kvm_arm.h
View File

@ -91,7 +91,7 @@
#define HCR_HOST_VHE_FLAGS (HCR_RW | HCR_TGE | HCR_E2H)
/* TCR_EL2 Registers bits */
#define TCR_EL2_RES1 ((1 << 31) | (1 << 23))
#define TCR_EL2_RES1 ((1U << 31) | (1 << 23))
#define TCR_EL2_TBI (1 << 20)
#define TCR_EL2_PS_SHIFT 16
#define TCR_EL2_PS_MASK (7 << TCR_EL2_PS_SHIFT)
@ -276,7 +276,7 @@
#define CPTR_EL2_TFP_SHIFT 10
/* Hyp Coprocessor Trap Register */
#define CPTR_EL2_TCPAC (1 << 31)
#define CPTR_EL2_TCPAC (1U << 31)
#define CPTR_EL2_TAM (1 << 30)
#define CPTR_EL2_TTA (1 << 20)
#define CPTR_EL2_TFP (1 << CPTR_EL2_TFP_SHIFT)

14
arch/arm64/kvm/hyp/include/hyp/switch.h
View File

@ -403,6 +403,8 @@ typedef bool (*exit_handler_fn)(struct kvm_vcpu *, u64 *);
static const exit_handler_fn *kvm_get_exit_handler_array(struct kvm_vcpu *vcpu);
static void early_exit_filter(struct kvm_vcpu *vcpu, u64 *exit_code);
/*
* Allow the hypervisor to handle the exit with an exit handler if it has one.
*
@ -429,6 +431,18 @@ static inline bool kvm_hyp_handle_exit(struct kvm_vcpu *vcpu, u64 *exit_code)
*/
static inline bool fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code)
{
/*
* Save PSTATE early so that we can evaluate the vcpu mode
* early on.
*/
vcpu->arch.ctxt.regs.pstate = read_sysreg_el2(SYS_SPSR);
/*
* Check whether we want to repaint the state one way or
* another.
*/
early_exit_filter(vcpu, exit_code);
if (ARM_EXCEPTION_CODE(*exit_code) != ARM_EXCEPTION_IRQ)
vcpu->arch.fault.esr_el2 = read_sysreg_el2(SYS_ESR);

7
arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
View File

@ -70,7 +70,12 @@ static inline void __sysreg_save_el1_state(struct kvm_cpu_context *ctxt)
static inline void __sysreg_save_el2_return_state(struct kvm_cpu_context *ctxt)
{
ctxt->regs.pc = read_sysreg_el2(SYS_ELR);
ctxt->regs.pstate = read_sysreg_el2(SYS_SPSR);
/*
* Guest PSTATE gets saved at guest fixup time in all
* cases. We still need to handle the nVHE host side here.
*/
if (!has_vhe() && ctxt->__hyp_running_vcpu)
ctxt->regs.pstate = read_sysreg_el2(SYS_SPSR);
if (cpus_have_final_cap(ARM64_HAS_RAS_EXTN))
ctxt_sys_reg(ctxt, DISR_EL1) = read_sysreg_s(SYS_VDISR_EL2);

8
arch/arm64/kvm/hyp/nvhe/switch.c
View File

@ -233,7 +233,7 @@ static const exit_handler_fn *kvm_get_exit_handler_array(struct kvm_vcpu *vcpu)
* Returns false if the guest ran in AArch32 when it shouldn't have, and
* thus should exit to the host, or true if a the guest run loop can continue.
*/
static bool handle_aarch32_guest(struct kvm_vcpu *vcpu, u64 *exit_code)
static void early_exit_filter(struct kvm_vcpu *vcpu, u64 *exit_code)
{
struct kvm *kvm = kern_hyp_va(vcpu->kvm);
@ -248,10 +248,7 @@ static bool handle_aarch32_guest(struct kvm_vcpu *vcpu, u64 *exit_code)
vcpu->arch.target = -1;
*exit_code &= BIT(ARM_EXIT_WITH_SERROR_BIT);
*exit_code |= ARM_EXCEPTION_IL;
return false;
}
return true;
}
/* Switch to the guest for legacy non-VHE systems */
@ -316,9 +313,6 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
/* Jump in the fire! */
exit_code = __guest_enter(vcpu);
if (unlikely(!handle_aarch32_guest(vcpu, &exit_code)))
break;
/* And we're baaack! */
} while (fixup_guest_exit(vcpu, &exit_code));

4
arch/arm64/kvm/hyp/vhe/switch.c
View File

@ -112,6 +112,10 @@ static const exit_handler_fn *kvm_get_exit_handler_array(struct kvm_vcpu *vcpu)
return hyp_exit_handlers;
}
static void early_exit_filter(struct kvm_vcpu *vcpu, u64 *exit_code)
{
}
/* Switch to the guest for VHE systems running in EL2 */
static int __kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
{