linux-kernel - [PATCH 4.14 044/211] KVM: nVMX: reset cache/shadows when switching loaded VMCS

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Message-Id: <20191127203058.337637590@linuxfoundation.org>
Date:   Wed, 27 Nov 2019 21:29:37 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Jim Mattson <jmattson@...gle.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.14 044/211] KVM: nVMX: reset cache/shadows when switching loaded VMCS

From: Sean Christopherson <sean.j.christopherson@...el.com>

[ Upstream commit b7031fd40fcc741b0f9b0c04c8d844e445858b84 ]

Reset the vm_{entry,exit}_controls_shadow variables as well as the
segment cache after loading a new VMCS in vmx_switch_vmcs().  The
shadows/cache track VMCS data, i.e. they're stale every time we
switch to a new VMCS regardless of reason.

This fixes a bug where stale control shadows would be consumed after
a nested VMExit due to a failed consistency check.

Suggested-by: Jim Mattson <jmattson@...gle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
Reviewed-by: Jim Mattson <jmattson@...gle.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/x86/kvm/vmx.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index ab6384efc7916..1c4e5eb8be835 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -10000,6 +10000,10 @@ static void vmx_switch_vmcs(struct kvm_vcpu *vcpu, struct loaded_vmcs *vmcs)
 	vmx_vcpu_load(vcpu, cpu);
 	vcpu->cpu = cpu;
 	put_cpu();
+
+	vm_entry_controls_reset_shadow(vmx);
+	vm_exit_controls_reset_shadow(vmx);
+	vmx_segment_cache_clear(vmx);
 }
 
 /*
@@ -11428,7 +11432,6 @@ static int enter_vmx_non_root_mode(struct kvm_vcpu *vcpu, bool from_vmentry)
 		vmx->nested.vmcs01_debugctl = vmcs_read64(GUEST_IA32_DEBUGCTL);
 
 	vmx_switch_vmcs(vcpu, &vmx->nested.vmcs02);
-	vmx_segment_cache_clear(vmx);
 
 	if (prepare_vmcs02(vcpu, vmcs12, from_vmentry, &exit_qual)) {
 		leave_guest_mode(vcpu);
@@ -12172,9 +12175,6 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
 	}
 
 	vmx_switch_vmcs(vcpu, &vmx->vmcs01);
-	vm_entry_controls_reset_shadow(vmx);
-	vm_exit_controls_reset_shadow(vmx);
-	vmx_segment_cache_clear(vmx);
 
 	/* Update any VMCS fields that might have changed while L2 ran */
 	vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, vmx->msr_autoload.host.nr);
-- 
2.20.1