Patch-mainline: v5.17-rc1
Git-commit: b84155c38076b36d625043a06a2f1c90bde62903
References: git-fixes
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Mon, 29 Nov 2021 10:47:02 +0100
Subject: [PATCH] KVM: VMX: Introduce vmx_msr_bitmap_l01_changed() helper
In preparation to enabling 'Enlightened MSR Bitmap' feature for Hyper-V
guests move MSR bitmap update tracking to a dedicated helper.
Note: vmx_msr_bitmap_l01_changed() is called when MSR bitmap might be
updated. KVM doesn't check if the bit we're trying to set is already set
(or the bit it's trying to clear is already cleared). Such situations
should not be common and a few false positives should not be a problem.
No functional change intended.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211129094704.326635-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
---
arch/x86/kvm/vmx/vmx.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 9d7f26eaf05f..7ee50671191b 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -3688,6 +3688,17 @@ void free_vpid(int vpid)
spin_unlock(&vmx_vpid_lock);
}
+static void vmx_msr_bitmap_l01_changed(struct vcpu_vmx *vmx)
+{
+ /*
+ * When KVM is a nested hypervisor on top of Hyper-V and uses
+ * 'Enlightened MSR Bitmap' feature L0 needs to know that MSR
+ * bitmap has changed.
+ */
+ if (static_branch_unlikely(&enable_evmcs))
+ evmcs_touch_msr_bitmap();
+}
+
void vmx_disable_intercept_for_msr(struct kvm_vcpu *vcpu, u32 msr, int type)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
@@ -3696,8 +3707,7 @@ void vmx_disable_intercept_for_msr(struct kvm_vcpu *vcpu, u32 msr, int type)
if (!cpu_has_vmx_msr_bitmap())
return;
- if (static_branch_unlikely(&enable_evmcs))
- evmcs_touch_msr_bitmap();
+ vmx_msr_bitmap_l01_changed(vmx);
/*
* Mark the desired intercept state in shadow bitmap, this is needed
@@ -3741,8 +3751,7 @@ void vmx_enable_intercept_for_msr(struct kvm_vcpu *vcpu, u32 msr, int type)
if (!cpu_has_vmx_msr_bitmap())
return;
- if (static_branch_unlikely(&enable_evmcs))
- evmcs_touch_msr_bitmap();
+ vmx_msr_bitmap_l01_changed(vmx);
/*
* Mark the desired intercept state in shadow bitmap, this is needed
--
2.35.3