[PATCH 2/8] KVM: arm64: Avoid corrupting vCPU context register in guest exit
From: Marc Zyngier <maz@kernel.org>
Date: 2021-03-05 18:53:58
Also in:
kvm, kvmarm, stable
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
From: Will Deacon <will@kernel.org>
Commit 7db21530479f ("KVM: arm64: Restore hyp when panicking in guest
context") tracks the currently running vCPU, clearing the pointer to
NULL on exit from a guest.
Unfortunately, the use of 'set_loaded_vcpu' clobbers x1 to point at the
kvm_hyp_ctxt instead of the vCPU context, causing the subsequent RAS
code to go off into the weeds when it saves the DISR assuming that the
CPU context is embedded in a struct vCPU.
Leave x1 alone and use x3 as a temporary register instead when clearing
the vCPU on the guest exit path.
Cc: Marc Zyngier <maz@kernel.org>
Cc: Andrew Scull <redacted>
Cc: <redacted>
Fixes: 7db21530479f ("KVM: arm64: Restore hyp when panicking in guest context")
Suggested-by: Quentin Perret <redacted>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210226181211.14542-1-will@kernel.org (local)
---
arch/arm64/kvm/hyp/entry.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index b0afad7a99c6..0c66a1d408fd 100644
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S@@ -146,7 +146,7 @@ SYM_INNER_LABEL(__guest_exit, SYM_L_GLOBAL) // Now restore the hyp regs restore_callee_saved_regs x2 - set_loaded_vcpu xzr, x1, x2 + set_loaded_vcpu xzr, x2, x3 alternative_if ARM64_HAS_RAS_EXTN // If we have the RAS extensions we can consume a pending error
--
2.29.2
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