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authorJames Morse <james.morse@arm.com>2018-07-20 10:56:13 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-07-22 14:27:40 +0200
commit02891fdbfd1e61feec902b640d9eb415f04de693 (patch)
tree9e9e623c7c820621ee1069f7ec8e76c4adeb982f
parentc488ae439ded49d20fcd264dec39f30300bbd2c1 (diff)
KVM: arm64: Store vcpu on the stack during __guest_enter()
Commit 32b03d1059667a39e089c45ee38ec9c16332430f upstream. KVM uses tpidr_el2 as its private vcpu register, which makes sense for non-vhe world switch as only KVM can access this register. This means vhe Linux has to use tpidr_el1, which KVM has to save/restore as part of the host context. If the SDEI handler code runs behind KVMs back, it mustn't access any per-cpu variables. To allow this on systems with vhe we need to make the host use tpidr_el2, saving KVM from save/restoring it. __guest_enter() stores the host_ctxt on the stack, do the same with the vcpu. 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> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/arm64/kvm/hyp/entry.S10
-rw-r--r--arch/arm64/kvm/hyp/hyp-entry.S6
2 files changed, 10 insertions, 6 deletions
diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index 12ee62d6d410..9a8ab5dddd9e 100644
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -62,8 +62,8 @@ ENTRY(__guest_enter)
// Store the host regs
save_callee_saved_regs x1
- // Store the host_ctxt for use at exit time
- str x1, [sp, #-16]!
+ // Store host_ctxt and vcpu for use at exit time
+ stp x1, x0, [sp, #-16]!
add x18, x0, #VCPU_CONTEXT
@@ -159,6 +159,10 @@ abort_guest_exit_end:
ENDPROC(__guest_exit)
ENTRY(__fpsimd_guest_restore)
+ // x0: esr
+ // x1: vcpu
+ // x2-x29,lr: vcpu regs
+ // vcpu x0-x1 on the stack
stp x2, x3, [sp, #-16]!
stp x4, lr, [sp, #-16]!
@@ -173,7 +177,7 @@ alternative_else
alternative_endif
isb
- mrs x3, tpidr_el2
+ mov x3, x1
ldr x0, [x3, #VCPU_HOST_CONTEXT]
kern_hyp_va x0
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 4e9d50c3e658..acd75c905084 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -121,24 +121,24 @@ el1_trap:
/*
* x0: ESR_EC
*/
+ ldr x1, [sp, #16 + 8] // vcpu stored by __guest_enter
/* Guest accessed VFP/SIMD registers, save host, restore Guest */
cmp x0, #ESR_ELx_EC_FP_ASIMD
b.eq __fpsimd_guest_restore
- mrs x1, tpidr_el2
mov x0, #ARM_EXCEPTION_TRAP
b __guest_exit
el1_irq:
stp x0, x1, [sp, #-16]!
- mrs x1, tpidr_el2
+ ldr x1, [sp, #16 + 8]
mov x0, #ARM_EXCEPTION_IRQ
b __guest_exit
el1_error:
stp x0, x1, [sp, #-16]!
- mrs x1, tpidr_el2
+ ldr x1, [sp, #16 + 8]
mov x0, #ARM_EXCEPTION_EL1_SERROR
b __guest_exit