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[07/43] KVM: VMX: Remove explicit MMU reset in enter_rmode()

Message ID 20210424004645.3950558-8-seanjc@google.com (mailing list archive)
State New, archived
Headers show
Series KVM: x86: vCPU RESET/INIT fixes and consolidation | expand

Commit Message

Sean Christopherson April 24, 2021, 12:46 a.m. UTC
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 <seanjc@google.com>
---
 arch/x86/kvm/vmx/vmx.c | 2 --
 1 file changed, 2 deletions(-)
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Patch

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 9c00d013af59..e90952ca6087 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2960,8 +2960,6 @@  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)