[PATCH AUTOSEL 4.19 047/237] KVM: nVMX: reset cache/shadows when switching loaded VMCS

Sasha Levin
2019-11-16T16:25:38Z

From: Sean Christopherson <sean.j.christopherson@intel.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@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.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 4eda2a9c234a6..8c7554d7f0a80 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -11013,6 +11013,10 @@ static void vmx_switch_vmcs(struct kvm_vcpu *vcpu, struct loaded_vmcs *vmcs)
vmx->loaded_vmcs = vmcs;
vmx_vcpu_load(vcpu, cpu);
put_cpu();
+
+ vm_entry_controls_reset_shadow(vmx);
+ vm_exit_controls_reset_shadow(vmx);
+ vmx_segment_cache_clear(vmx);
}

/*
@@ -12700,7 +12704,6 @@ static int enter_vmx_non_root_mode(struct kvm_vcpu *vcpu, u32 *exit_qual)
vmx->nested.vmcs01_guest_bndcfgs = vmcs_read64(GUEST_BNDCFGS);

vmx_switch_vmcs(vcpu, &vmx->nested.vmcs02);
- vmx_segment_cache_clear(vmx);

if (vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_TSC_OFFSETING)
vcpu->arch.tsc_offset += vmcs12->tsc_offset;
@@ -13531,9 +13534,6 @@ 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