[RFC PATCH v6 24/36] KVM: VMX: Tweak the special handling of SECONDARY_EXEC_ENCLS_EXITING in setup_vmcs_config()

Sean Christopherson
2022-08-24T03:04:37Z

SECONDARY_EXEC_ENCLS_EXITING is the only control which is conditionally
added to the 'optional' checklist in setup_vmcs_config() but the special
case can be avoided by always checking for its presence first and filtering
out the result later.

Note: the situation when SECONDARY_EXEC_ENCLS_EXITING is present but
cpu_has_sgx() is false is possible when SGX is "soft-disabled", e.g. if
software writes MCE control MSRs or there's an uncorrectable #MC.

Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/vmx/vmx.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 7acbe43030e4..e694eb2190f3 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2601,9 +2601,9 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf,
SECONDARY_EXEC_PT_CONCEAL_VMX |
SECONDARY_EXEC_ENABLE_VMFUNC |
SECONDARY_EXEC_BUS_LOCK_DETECTION |
- SECONDARY_EXEC_NOTIFY_VM_EXITING;
- if (cpu_has_sgx())
- opt2 |= SECONDARY_EXEC_ENCLS_EXITING;
+ SECONDARY_EXEC_NOTIFY_VM_EXITING |
+ SECONDARY_EXEC_ENCLS_EXITING;
+
if (adjust_vmx_controls(min2, opt2,
MSR_IA32_VMX_PROCBASED_CTLS2,
&_cpu_based_2nd_exec_control) < 0)
@@ -2650,6 +2650,9 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf,
vmx_cap->vpid = 0;
}

+ if (!cpu_has_sgx())
+ _cpu_based_2nd_exec_control &= ~SECONDARY_EXEC_ENCLS_EXITING;
+
if (_cpu_based_exec_control & CPU_BASED_ACTIVATE_TERTIARY_CONTROLS) {
u64 opt3 = TERTIARY_EXEC_IPI_VIRT;

--
2.37.1.595.g718a3a8f04-goog