From 9544f33456fdd8663fd18d9cc215f1ce17bbcaf8 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 26 Feb 2021 18:12:11 +0000 Subject: [PATCH] FROMGIT: KVM: arm64: Avoid corrupting vCPU context register in guest exit 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 Cc: Andrew Scull Cc: Fixes: 7db21530479f ("KVM: arm64: Restore hyp when panicking in guest context") Suggested-by: Quentin Perret Signed-off-by: Will Deacon Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20210226181211.14542-1-will@kernel.org (cherry picked from commit a8a0f5dbcdf57d89bb8d555c6423763d99a156c1 git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git fixes) Signed-off-by: Will Deacon Bug: 178098380 Test: atest VirtualizationHostTestCases on an EL2-enabled device Change-Id: I0fe8c4696054db0f9a22621489b2e3ae833263fa --- 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