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arm64: KVM: HYP mode entry points

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Add the entry points for HYP mode (both for hypercalls and
exception handling).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
This commit is contained in:
Marc Zyngier 2015-10-25 08:01:56 +00:00
parent 5eec0a91e3
commit 2b28162cf6
2 changed files with 204 additions and 0 deletions
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1
arch/arm64/kvm/hyp/Makefile
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@ -11,3 +11,4 @@ obj-$(CONFIG_KVM_ARM_HOST) += entry.o
obj-$(CONFIG_KVM_ARM_HOST) += switch.o
obj-$(CONFIG_KVM_ARM_HOST) += fpsimd.o
obj-$(CONFIG_KVM_ARM_HOST) += tlb.o
obj-$(CONFIG_KVM_ARM_HOST) += hyp-entry.o

203
arch/arm64/kvm/hyp/hyp-entry.S Normal file
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@ -0,0 +1,203 @@
/*
* Copyright (C) 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/linkage.h>
#include <asm/alternative.h>
#include <asm/assembler.h>
#include <asm/asm-offsets.h>
#include <asm/cpufeature.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_mmu.h>
.text
.pushsection .hyp.text, "ax"
.macro save_x0_to_x3
stp x0, x1, [sp, #-16]!
stp x2, x3, [sp, #-16]!
.endm
.macro restore_x0_to_x3
ldp x2, x3, [sp], #16
ldp x0, x1, [sp], #16
.endm
el1_sync: // Guest trapped into EL2
save_x0_to_x3
mrs x1, esr_el2
lsr x2, x1, #ESR_ELx_EC_SHIFT
cmp x2, #ESR_ELx_EC_HVC64
b.ne el1_trap
mrs x3, vttbr_el2 // If vttbr is valid, the 64bit guest
cbnz x3, el1_trap // called HVC
/* Here, we're pretty sure the host called HVC. */
restore_x0_to_x3
/* Check for __hyp_get_vectors */
cbnz x0, 1f
mrs x0, vbar_el2
b 2f
1: stp lr, xzr, [sp, #-16]!
/*
* Compute the function address in EL2, and shuffle the parameters.
*/
kern_hyp_va x0
mov lr, x0
mov x0, x1
mov x1, x2
mov x2, x3
blr lr
ldp lr, xzr, [sp], #16
2: eret
el1_trap:
/*
* x1: ESR
* x2: ESR_EC
*/
/* Guest accessed VFP/SIMD registers, save host, restore Guest */
cmp x2, #ESR_ELx_EC_FP_ASIMD
b.eq __fpsimd_guest_restore
cmp x2, #ESR_ELx_EC_DABT_LOW
mov x0, #ESR_ELx_EC_IABT_LOW
ccmp x2, x0, #4, ne
b.ne 1f // Not an abort we care about
/* This is an abort. Check for permission fault */
alternative_if_not ARM64_WORKAROUND_834220
and x2, x1, #ESR_ELx_FSC_TYPE
cmp x2, #FSC_PERM
b.ne 1f // Not a permission fault
alternative_else
nop // Use the permission fault path to
nop // check for a valid S1 translation,
nop // regardless of the ESR value.
alternative_endif
/*
* Check for Stage-1 page table walk, which is guaranteed
* to give a valid HPFAR_EL2.
*/
tbnz x1, #7, 1f // S1PTW is set
/* Preserve PAR_EL1 */
mrs x3, par_el1
stp x3, xzr, [sp, #-16]!
/*
* Permission fault, HPFAR_EL2 is invalid.
* Resolve the IPA the hard way using the guest VA.
* Stage-1 translation already validated the memory access rights.
* As such, we can use the EL1 translation regime, and don't have
* to distinguish between EL0 and EL1 access.
*/
mrs x2, far_el2
at s1e1r, x2
isb
/* Read result */
mrs x3, par_el1
ldp x0, xzr, [sp], #16 // Restore PAR_EL1 from the stack
msr par_el1, x0
tbnz x3, #0, 3f // Bail out if we failed the translation
ubfx x3, x3, #12, #36 // Extract IPA
lsl x3, x3, #4 // and present it like HPFAR
b 2f
1: mrs x3, hpfar_el2
mrs x2, far_el2
2: mrs x0, tpidr_el2
str w1, [x0, #VCPU_ESR_EL2]
str x2, [x0, #VCPU_FAR_EL2]
str x3, [x0, #VCPU_HPFAR_EL2]
mov x1, #ARM_EXCEPTION_TRAP
b __guest_exit
/*
* Translation failed. Just return to the guest and
* let it fault again. Another CPU is probably playing
* behind our back.
*/
3: restore_x0_to_x3
eret
el1_irq:
save_x0_to_x3
mrs x0, tpidr_el2
mov x1, #ARM_EXCEPTION_IRQ
b __guest_exit
.macro invalid_vector label, target = __kvm_hyp_panic
.align 2
\label:
b \target
ENDPROC(\label)
.endm
/* None of these should ever happen */
invalid_vector el2t_sync_invalid
invalid_vector el2t_irq_invalid
invalid_vector el2t_fiq_invalid
invalid_vector el2t_error_invalid
invalid_vector el2h_sync_invalid
invalid_vector el2h_irq_invalid
invalid_vector el2h_fiq_invalid
invalid_vector el2h_error_invalid
invalid_vector el1_sync_invalid
invalid_vector el1_irq_invalid
invalid_vector el1_fiq_invalid
invalid_vector el1_error_invalid
.ltorg
.align 11
ENTRY(__hyp_vector)
ventry el2t_sync_invalid // Synchronous EL2t
ventry el2t_irq_invalid // IRQ EL2t
ventry el2t_fiq_invalid // FIQ EL2t
ventry el2t_error_invalid // Error EL2t
ventry el2h_sync_invalid // Synchronous EL2h
ventry el2h_irq_invalid // IRQ EL2h
ventry el2h_fiq_invalid // FIQ EL2h
ventry el2h_error_invalid // Error EL2h
ventry el1_sync // Synchronous 64-bit EL1
ventry el1_irq // IRQ 64-bit EL1
ventry el1_fiq_invalid // FIQ 64-bit EL1
ventry el1_error_invalid // Error 64-bit EL1
ventry el1_sync // Synchronous 32-bit EL1
ventry el1_irq // IRQ 32-bit EL1
ventry el1_fiq_invalid // FIQ 32-bit EL1
ventry el1_error_invalid // Error 32-bit EL1
ENDPROC(__hyp_vector)