[PATCH v6 37/44] KVM: VMX: Dedup code for removing MSR from VMCS's auto-load list

Sean Christopherson
2025-12-06T00:18:42Z

Add a helper to remove an MSR from an auto-{load,store} list to dedup the
msr_autoload code, and in anticipation of adding similar functionality for
msr_autostore.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/vmx/vmx.c | 31 ++++++++++++++++---------------
1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 52bcb817cc15..a51f66d1b201 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1040,9 +1040,22 @@ static int vmx_find_loadstore_msr_slot(struct vmx_msrs *m, u32 msr)
return -ENOENT;
}

+static void vmx_remove_auto_msr(struct vmx_msrs *m, u32 msr,
+ unsigned long vmcs_count_field)
+{
+ int i;
+
+ i = vmx_find_loadstore_msr_slot(m, msr);
+ if (i < 0)
+ return;
+
+ --m->nr;
+ m->val[i] = m->val[m->nr];
+ vmcs_write32(vmcs_count_field, m->nr);
+}
+
static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
{
- int i;
struct msr_autoload *m = &vmx->msr_autoload;

switch (msr) {
@@ -1063,21 +1076,9 @@ static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
}
break;
}
- i = vmx_find_loadstore_msr_slot(&m->guest, msr);
- if (i < 0)
- goto skip_guest;
- --m->guest.nr;
- m->guest.val[i] = m->guest.val[m->guest.nr];
- vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->guest.nr);

-skip_guest:
- i = vmx_find_loadstore_msr_slot(&m->host, msr);
- if (i < 0)
- return;
-
- --m->host.nr;
- m->host.val[i] = m->host.val[m->host.nr];
- vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->host.nr);
+ vmx_remove_auto_msr(&m->guest, msr, VM_ENTRY_MSR_LOAD_COUNT);
+ vmx_remove_auto_msr(&m->host, msr, VM_EXIT_MSR_LOAD_COUNT);
}

static __always_inline void add_atomic_switch_msr_special(struct vcpu_vmx *vmx,
--
2.52.0.223.gf5cc29aaa4-goog