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authorPaolo Bonzini <pbonzini@redhat.com>2018-10-03 10:34:00 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2018-10-04 13:40:44 +0200
commit2cf7ea9f40fabee0f8b40db4eb2d1e85cc6c0a95 (patch)
treea2fac261c821b28d52f42e54eaa725d08654d895 /arch/x86/kvm/vmx.c
parentKVM: VMX: check for existence of secondary exec controls before accessing (diff)
downloadlinux-2cf7ea9f40fabee0f8b40db4eb2d1e85cc6c0a95.tar.xz
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KVM: VMX: hide flexpriority from guest when disabled at the module level
As of commit 8d860bbeedef ("kvm: vmx: Basic APIC virtualization controls have three settings"), KVM will disable VIRTUALIZE_APIC_ACCESSES when a nested guest writes APIC_BASE MSR and kvm-intel.flexpriority=0, whereas previously KVM would allow a nested guest to enable VIRTUALIZE_APIC_ACCESSES so long as it's supported in hardware. That is, KVM now advertises VIRTUALIZE_APIC_ACCESSES to a guest but doesn't (always) allow setting it when kvm-intel.flexpriority=0, and may even initially allow the control and then clear it when the nested guest writes APIC_BASE MSR, which is decidedly odd even if it doesn't cause functional issues. Hide the control completely when the module parameter is cleared. reported-by: Sean Christopherson <sean.j.christopherson@intel.com> Fixes: 8d860bbeedef ("kvm: vmx: Basic APIC virtualization controls have three settings") Cc: Jim Mattson <jmattson@google.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to '')
-rw-r--r--arch/x86/kvm/vmx.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 764ae031054f..55b62760b694 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3589,12 +3589,12 @@ static void nested_vmx_setup_ctls_msrs(struct nested_vmx_msrs *msrs, bool apicv)
msrs->secondary_ctls_high);
msrs->secondary_ctls_low = 0;
msrs->secondary_ctls_high &=
- SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
SECONDARY_EXEC_DESC |
SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE |
SECONDARY_EXEC_APIC_REGISTER_VIRT |
SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
SECONDARY_EXEC_WBINVD_EXITING;
+
/*
* We can emulate "VMCS shadowing," even if the hardware
* doesn't support it.
@@ -3651,6 +3651,10 @@ static void nested_vmx_setup_ctls_msrs(struct nested_vmx_msrs *msrs, bool apicv)
msrs->secondary_ctls_high |=
SECONDARY_EXEC_UNRESTRICTED_GUEST;
+ if (flexpriority_enabled)
+ msrs->secondary_ctls_high |=
+ SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
+
/* miscellaneous data */
rdmsr(MSR_IA32_VMX_MISC,
msrs->misc_low,