This is a note to let you know that I've just added the patch titled
arm/arm64: KVM: Complete WFI/WFE instructions
to the 3.16-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm-arm64-kvm-complete-wfi-wfe-instructions.patch
and it can be found in the queue-3.16 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 05e0127f9e362b36aa35f17b1a3d52bca9322a3a Mon Sep 17 00:00:00 2001
From: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Date: Tue, 26 Aug 2014 14:33:02 +0200
Subject: arm/arm64: KVM: Complete WFI/WFE instructions
From: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
commit 05e0127f9e362b36aa35f17b1a3d52bca9322a3a upstream.
The architecture specifies that when the processor wakes up from a WFE
or WFI instruction, the instruction is considered complete, however we
currrently return to EL1 (or EL0) at the WFI/WFE instruction itself.
While most guests may not be affected by this because their local
exception handler performs an exception returning setting the event bit
or with an interrupt pending, some guests like UEFI will get wedged due
this little mishap.
Simply skip the instruction when we have completed the emulation.
Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/kvm/handle_exit.c | 2 ++
arch/arm64/kvm/handle_exit.c | 2 ++
2 files changed, 4 insertions(+)
--- a/arch/arm/kvm/handle_exit.c
+++ b/arch/arm/kvm/handle_exit.c
@@ -93,6 +93,8 @@ static int kvm_handle_wfx(struct kvm_vcp
else
kvm_vcpu_block(vcpu);
+ kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
+
return 1;
}
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -66,6 +66,8 @@ static int kvm_handle_wfx(struct kvm_vcp
else
kvm_vcpu_block(vcpu);
+ kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
+
return 1;
}
Patches currently in stable-queue which might be from christoffer.dall@xxxxxxxxxx are
queue-3.16/arm-arm64-kvm-complete-wfi-wfe-instructions.patch
queue-3.16/arm-arm64-kvm-nuke-hyp-mode-tlbs-before-enabling-mmu.patch
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