[PATCH v2 08/13] KVM: SVM: Rename vmcb->virt_ext to vmcb->misc_ctl2

Yosry Ahmed
2025-11-10T22:29:57Z

'virt' is confusing in the VMCB because it is relative and ambiguous.
The 'virt_ext' field includes bits for LBR virtualization and
VMSAVE/VMLOAD virtualization, so it's just another miscellaneous control
field. Name it as such.

While at it, move the definitions of the bits below those for
'misc_ctl' and rename them for consistency.

Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
---
arch/x86/include/asm/svm.h | 7 +++----
arch/x86/kvm/svm/nested.c | 18 ++++++++---------
arch/x86/kvm/svm/svm.c | 20 +++++++++----------
arch/x86/kvm/svm/svm.h | 2 +-
tools/testing/selftests/kvm/include/x86/svm.h | 8 ++++----
.../selftests/kvm/x86/svm_lbr_nested_state.c | 4 ++--
6 files changed, 29 insertions(+), 30 deletions(-)

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 76ec1d40e6461..a842018952d2c 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -148,7 +148,7 @@ struct __attribute__ ((__packed__)) vmcb_control_area {
u32 event_inj;
u32 event_inj_err;
u64 nested_cr3;
- u64 virt_ext;
+ u64 misc_ctl2;
u32 clean;
u32 reserved_5;
u64 next_rip;
@@ -219,9 +219,6 @@ struct __attribute__ ((__packed__)) vmcb_control_area {
#define X2APIC_MODE_SHIFT 30
#define X2APIC_MODE_MASK (1 << X2APIC_MODE_SHIFT)

-#define LBR_CTL_ENABLE_MASK BIT_ULL(0)
-#define VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK BIT_ULL(1)
-
#define SVM_INTERRUPT_SHADOW_MASK BIT_ULL(0)
#define SVM_GUEST_INTERRUPT_MASK BIT_ULL(1)

@@ -240,6 +237,8 @@ struct __attribute__ ((__packed__)) vmcb_control_area {
#define SVM_MISC_CTL_SEV_ENABLE BIT(1)
#define SVM_MISC_CTL_SEV_ES_ENABLE BIT(2)

+#define SVM_MISC_CTL2_LBR_CTL_ENABLE BIT_ULL(0)
+#define SVM_MISC_CTL2_V_VMLOAD_VMSAVE_ENABLE BIT_ULL(1)

#define SVM_TSC_RATIO_RSVD 0xffffff0000000000ULL
#define SVM_TSC_RATIO_MIN 0x0000000000000001ULL
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 2a5c3788f954b..b8d65832c64de 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -117,7 +117,7 @@ static bool nested_vmcb_needs_vls_intercept(struct vcpu_svm *svm)
if (!nested_npt_enabled(svm))
return true;

- if (!(svm->nested.ctl.virt_ext & VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK))
+ if (!(svm->nested.ctl.misc_ctl2 & SVM_MISC_CTL2_V_VMLOAD_VMSAVE_ENABLE))
return true;

return false;
@@ -180,7 +180,7 @@ void recalc_intercepts(struct vcpu_svm *svm)
vmcb_set_intercept(c, INTERCEPT_VMLOAD);
vmcb_set_intercept(c, INTERCEPT_VMSAVE);
} else {
- WARN_ON(!(c->virt_ext & VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK));
+ WARN_ON(!(c->misc_ctl2 & SVM_MISC_CTL2_V_VMLOAD_VMSAVE_ENABLE));
}
}

@@ -497,7 +497,7 @@ void __nested_copy_vmcb_control_to_cache(struct kvm_vcpu *vcpu,
to->event_inj_err = from->event_inj_err;
to->next_rip = from->next_rip;
to->nested_cr3 = from->nested_cr3;
- to->virt_ext = from->virt_ext;
+ to->misc_ctl2 = from->misc_ctl2;
to->pause_filter_count = from->pause_filter_count;
to->pause_filter_thresh = from->pause_filter_thresh;

@@ -738,7 +738,7 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12
}

if (unlikely(guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) &&
- (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {
+ (svm->nested.ctl.misc_ctl2 & SVM_MISC_CTL2_LBR_CTL_ENABLE))) {
/*
* Reserved bits of DEBUGCTL are ignored. Be consistent with
* svm_set_msr's definition of reserved bits.
@@ -902,10 +902,10 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm,
svm->soft_int_next_rip = vmcb12_rip;
}

- /* LBR_CTL_ENABLE_MASK is controlled by svm_update_lbrv() */
+ /* SVM_MISC_CTL2_LBR_CTL_ENABLE is controlled by svm_update_lbrv() */

if (!nested_vmcb_needs_vls_intercept(svm))
- vmcb02->control.virt_ext |= VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK;
+ vmcb02->control.misc_ctl2 |= SVM_MISC_CTL2_V_VMLOAD_VMSAVE_ENABLE;

if (guest_cpu_cap_has(vcpu, X86_FEATURE_PAUSEFILTER))
pause_count12 = svm->nested.ctl.pause_filter_count;
@@ -1257,7 +1257,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
kvm_make_request(KVM_REQ_EVENT, &svm->vcpu);

if (unlikely(guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) &&
- (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {
+ (svm->nested.ctl.misc_ctl2 & SVM_MISC_CTL2_LBR_CTL_ENABLE))) {
svm_copy_lbrs(&vmcb12->save, &vmcb02->save);
} else {
svm_copy_lbrs(&vmcb01->save, &vmcb02->save);
@@ -1763,8 +1763,8 @@ static void nested_copy_vmcb_cache_to_control(struct vmcb_control_area *dst,
dst->event_inj = from->event_inj;
dst->event_inj_err = from->event_inj_err;
dst->next_rip = from->next_rip;
- dst->nested_cr3 = from->nested_cr3;
- dst->virt_ext = from->virt_ext;
+ dst->nested_cr3 = from->nested_cr3;
+ dst->misc_ctl2 = from->misc_ctl2;
dst->pause_filter_count = from->pause_filter_count;
dst->pause_filter_thresh = from->pause_filter_thresh;
/* 'clean' and 'hv_enlightenments' are not changed by KVM */
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index b5b4965e6bfdd..9789f7e72ae97 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -705,7 +705,7 @@ void *svm_alloc_permissions_map(unsigned long size, gfp_t gfp_mask)

static void svm_recalc_lbr_msr_intercepts(struct kvm_vcpu *vcpu)
{
- bool intercept = !(to_svm(vcpu)->vmcb->control.virt_ext & LBR_CTL_ENABLE_MASK);
+ bool intercept = !(to_svm(vcpu)->vmcb->control.misc_ctl2 & SVM_MISC_CTL2_LBR_CTL_ENABLE);

svm_set_intercept_for_msr(vcpu, MSR_IA32_LASTBRANCHFROMIP, MSR_TYPE_RW, intercept);
svm_set_intercept_for_msr(vcpu, MSR_IA32_LASTBRANCHTOIP, MSR_TYPE_RW, intercept);
@@ -797,7 +797,7 @@ static void svm_recalc_msr_intercepts(struct kvm_vcpu *vcpu)

static void __svm_enable_lbrv(struct kvm_vcpu *vcpu)
{
- to_svm(vcpu)->vmcb->control.virt_ext |= LBR_CTL_ENABLE_MASK;
+ to_svm(vcpu)->vmcb->control.misc_ctl2 |= SVM_MISC_CTL2_LBR_CTL_ENABLE;
}

void svm_enable_lbrv(struct kvm_vcpu *vcpu)
@@ -809,16 +809,16 @@ void svm_enable_lbrv(struct kvm_vcpu *vcpu)
static void __svm_disable_lbrv(struct kvm_vcpu *vcpu)
{
KVM_BUG_ON(sev_es_guest(vcpu->kvm), vcpu->kvm);
- to_svm(vcpu)->vmcb->control.virt_ext &= ~LBR_CTL_ENABLE_MASK;
+ to_svm(vcpu)->vmcb->control.misc_ctl2 &= ~SVM_MISC_CTL2_LBR_CTL_ENABLE;
}

void svm_update_lbrv(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
- bool current_enable_lbrv = svm->vmcb->control.virt_ext & LBR_CTL_ENABLE_MASK;
+ bool current_enable_lbrv = svm->vmcb->control.misc_ctl2 & SVM_MISC_CTL2_LBR_CTL_ENABLE;
bool enable_lbrv = (svm->vmcb->save.dbgctl & DEBUGCTLMSR_LBR) ||
(is_guest_mode(vcpu) && guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) &&
- (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK));
+ (svm->nested.ctl.misc_ctl2 & SVM_MISC_CTL2_LBR_CTL_ENABLE));

if (enable_lbrv && !current_enable_lbrv)
__svm_enable_lbrv(vcpu);
@@ -979,7 +979,7 @@ static void svm_recalc_instruction_intercepts(struct kvm_vcpu *vcpu)
if (guest_cpuid_is_intel_compatible(vcpu)) {
svm_set_intercept(svm, INTERCEPT_VMLOAD);
svm_set_intercept(svm, INTERCEPT_VMSAVE);
- svm->vmcb->control.virt_ext &= ~VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK;
+ svm->vmcb->control.misc_ctl2 &= ~SVM_MISC_CTL2_V_VMLOAD_VMSAVE_ENABLE;
} else {
/*
* If hardware supports Virtual VMLOAD VMSAVE then enable it
@@ -988,7 +988,7 @@ static void svm_recalc_instruction_intercepts(struct kvm_vcpu *vcpu)
if (vls) {
svm_clr_intercept(svm, INTERCEPT_VMLOAD);
svm_clr_intercept(svm, INTERCEPT_VMSAVE);
- svm->vmcb->control.virt_ext |= VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK;
+ svm->vmcb->control.misc_ctl2 |= SVM_MISC_CTL2_V_VMLOAD_VMSAVE_ENABLE;
}
}
}
@@ -3279,7 +3279,7 @@ static void dump_vmcb(struct kvm_vcpu *vcpu)
pr_err("%-20s%016llx\n", "ghcb:", control->ghcb_gpa);
pr_err("%-20s%08x\n", "event_inj:", control->event_inj);
pr_err("%-20s%08x\n", "event_inj_err:", control->event_inj_err);
- pr_err("%-20s%lld\n", "virt_ext:", control->virt_ext);
+ pr_err("%-20s%lld\n", "misc_ctl2:", control->misc_ctl2);
pr_err("%-20s%016llx\n", "next_rip:", control->next_rip);
pr_err("%-20s%016llx\n", "avic_backing_page:", control->avic_backing_page);
pr_err("%-20s%016llx\n", "avic_logical_id:", control->avic_logical_id);
@@ -4261,7 +4261,7 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu, u64 run_flags)
* VM-Exit), as running with the host's DEBUGCTL can negatively affect
* guest state and can even be fatal, e.g. due to Bus Lock Detect.
*/
- if (!(svm->vmcb->control.virt_ext & LBR_CTL_ENABLE_MASK) &&
+ if (!(svm->vmcb->control.misc_ctl2 & SVM_MISC_CTL2_LBR_CTL_ENABLE) &&
vcpu->arch.host_debugctl != svm->vmcb->save.dbgctl)
update_debugctlmsr(svm->vmcb->save.dbgctl);

@@ -4292,7 +4292,7 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu, u64 run_flags)
if (unlikely(svm->vmcb->control.exit_code == SVM_EXIT_NMI))
kvm_before_interrupt(vcpu, KVM_HANDLING_NMI);

- if (!(svm->vmcb->control.virt_ext & LBR_CTL_ENABLE_MASK) &&
+ if (!(svm->vmcb->control.misc_ctl2 & SVM_MISC_CTL2_LBR_CTL_ENABLE) &&
vcpu->arch.host_debugctl != svm->vmcb->save.dbgctl)
update_debugctlmsr(vcpu->arch.host_debugctl);

diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 861ed9c33977b..68be3a08e3e62 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -174,7 +174,7 @@ struct vmcb_ctrl_area_cached {
u32 event_inj_err;
u64 next_rip;
u64 nested_cr3;
- u64 virt_ext;
+ u64 misc_ctl2;
u32 clean;
u64 bus_lock_rip;
union {
diff --git a/tools/testing/selftests/kvm/include/x86/svm.h b/tools/testing/selftests/kvm/include/x86/svm.h
index 5d2bcce34c019..a3f4eadffeb46 100644
--- a/tools/testing/selftests/kvm/include/x86/svm.h
+++ b/tools/testing/selftests/kvm/include/x86/svm.h
@@ -104,7 +104,7 @@ struct __attribute__ ((__packed__)) vmcb_control_area {
u32 event_inj;
u32 event_inj_err;
u64 nested_cr3;
- u64 virt_ext;
+ u64 misc_ctl2;
u32 clean;
u32 reserved_5;
u64 next_rip;
@@ -156,9 +156,6 @@ struct __attribute__ ((__packed__)) vmcb_control_area {
#define AVIC_ENABLE_SHIFT 31
#define AVIC_ENABLE_MASK (1 << AVIC_ENABLE_SHIFT)

-#define LBR_CTL_ENABLE_MASK BIT_ULL(0)
-#define VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK BIT_ULL(1)
-
#define SVM_INTERRUPT_SHADOW_MASK 1

#define SVM_IOIO_STR_SHIFT 2
@@ -179,6 +176,9 @@ struct __attribute__ ((__packed__)) vmcb_control_area {
#define SVM_MISC_CTL_CTL_NP_ENABLE BIT(0)
#define SVM_MISC_CTL_SEV_ENABLE BIT(1)

+#define SVM_MISC_CTL2_LBR_CTL_ENABLE BIT_ULL(0)
+#define SVM_MISC_CTL2_V_VMLOAD_VMSAVE_ENABLE BIT_ULL(1)
+
struct __attribute__ ((__packed__)) vmcb_seg {
u16 selector;
u16 attrib;
diff --git a/tools/testing/selftests/kvm/x86/svm_lbr_nested_state.c b/tools/testing/selftests/kvm/x86/svm_lbr_nested_state.c
index a343279546fd8..4a9e644b8931e 100644
--- a/tools/testing/selftests/kvm/x86/svm_lbr_nested_state.c
+++ b/tools/testing/selftests/kvm/x86/svm_lbr_nested_state.c
@@ -75,9 +75,9 @@ static void l1_guest_code(struct svm_test_data *svm, bool nested_lbrv)
&l2_guest_stack[L2_GUEST_STACK_SIZE]);

if (nested_lbrv)
- vmcb->control.virt_ext = LBR_CTL_ENABLE_MASK;
+ vmcb->control.misc_ctl2 = SVM_MISC_CTL2_LBR_CTL_ENABLE;
else
- vmcb->control.virt_ext &= ~LBR_CTL_ENABLE_MASK;
+ vmcb->control.misc_ctl2 &= ~SVM_MISC_CTL2_LBR_CTL_ENABLE;

run_guest(vmcb, svm->vmcb_gpa);
GUEST_ASSERT(svm->vmcb->control.exit_code == SVM_EXIT_VMMCALL);
--
2.51.2.1041.gc1ab5b90ca-goog