[PATCH v2 2/2] KVM: nVMX: Simplify the setting of SECONDARY_EXEC_ENABLE_VMFUNC for nested.

From: Yu Zhang
Date: Wed Nov 09 2022 - 03:43:13 EST


Values of base settings for nested proc-based VM-Execution control MSR come
from the ones for non-nested. And for SECONDARY_EXEC_ENABLE_VMFUNC flag,
KVM currently a) first mask off it from vmcs_conf->cpu_based_2nd_exec_ctrl;
b) then check it against the same source; c) and reset it again if host has
it.

So just simplify this, by not masking off SECONDARY_EXEC_ENABLE_VMFUNC in
the first place.

No functional change.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Yu Zhang <yu.c.zhang@xxxxxxxxxxxxxxx>
---
arch/x86/kvm/vmx/nested.c | 14 +++++---------
1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 1acb81c2be11..2bad79985c10 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -6806,6 +6806,7 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps)
SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
SECONDARY_EXEC_RDRAND_EXITING |
SECONDARY_EXEC_ENABLE_INVPCID |
+ SECONDARY_EXEC_ENABLE_VMFUNC |
SECONDARY_EXEC_RDSEED_EXITING |
SECONDARY_EXEC_XSAVES |
SECONDARY_EXEC_TSC_SCALING;
@@ -6837,18 +6838,13 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps)
SECONDARY_EXEC_ENABLE_PML;
msrs->ept_caps |= VMX_EPT_AD_BIT;
}
- }

- if (cpu_has_vmx_vmfunc()) {
- msrs->secondary_ctls_high |=
- SECONDARY_EXEC_ENABLE_VMFUNC;
/*
- * Advertise EPTP switching unconditionally
- * since we emulate it
+ * Advertise EPTP switching irrespective of hardware support,
+ * KVM emulates it in software so long as VMFUNC is supported.
*/
- if (enable_ept)
- msrs->vmfunc_controls =
- VMX_VMFUNC_EPTP_SWITCHING;
+ if (cpu_has_vmx_vmfunc())
+ msrs->vmfunc_controls = VMX_VMFUNC_EPTP_SWITCHING;
}

/*
--
2.17.1