From 61152cd907d59ffd6b0a9479b2fa3b3b7b080409 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 13 Jul 2021 09:32:45 -0700 Subject: [PATCH] KVM: VMX: Remove explicit MMU reset in enter_rmode() Drop an explicit MMU reset when entering emulated real mode now that the vCPU INIT/RESET path correctly handles conditional MMU resets, e.g. if INIT arrives while the vCPU is in 64-bit mode. Note, while there are multiple other direct calls to vmx_set_cr0(), i.e. paths that change CR0 without invoking kvm_post_set_cr0(), only the INIT emulation can reach enter_rmode(). CLTS emulation only toggles CR.TS, VM-Exit (and late VM-Fail) emulation cannot architecturally transition to Real Mode, and VM-Enter to Real Mode is possible if and only if Unrestricted Guest is enabled (exposed to L1). This effectively reverts commit 8668a3c468ed ("KVM: VMX: Reset mmu context when entering real mode") Signed-off-by: Sean Christopherson Message-Id: <20210713163324.627647-8-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/vmx.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 6946a5161d38f..207393a429d1b 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -2852,8 +2852,6 @@ static void enter_rmode(struct kvm_vcpu *vcpu) fix_rmode_seg(VCPU_SREG_DS, &vmx->rmode.segs[VCPU_SREG_DS]); fix_rmode_seg(VCPU_SREG_GS, &vmx->rmode.segs[VCPU_SREG_GS]); fix_rmode_seg(VCPU_SREG_FS, &vmx->rmode.segs[VCPU_SREG_FS]); - - kvm_mmu_reset_context(vcpu); } int vmx_set_efer(struct kvm_vcpu *vcpu, u64 efer) -- 2.30.2