From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>,
Maxim Levitsky <mlevitsk@redhat.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH v4 6/8] KVM: VMX: Introduce vmx_msr_bitmap_l01_changed() helper
Date: Tue, 9 Nov 2021 17:28:33 +0100 [thread overview]
Message-ID: <20211109162835.99475-7-vkuznets@redhat.com> (raw)
In-Reply-To: <20211109162835.99475-1-vkuznets@redhat.com>
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>
---
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 fc87b6bbd277..1e6bf2cd7be0 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -3677,6 +3677,17 @@ 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);
@@ -3685,8 +3696,7 @@ 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
@@ -3730,8 +3740,7 @@ 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
--
2.31.1
next prev parent reply other threads:[~2021-11-09 18:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-09 16:28 [PATCH v4 0/8] KVM: nVMX: Enlightened MSR Bitmap feature for Hyper-V on KVM (+ KVM: x86: MSR filtering and related fixes) Vitaly Kuznetsov
2021-11-09 16:28 ` [PATCH v4 1/8] KVM: nVMX: Query current VMCS when determining if MSR bitmaps are in use Vitaly Kuznetsov
2021-11-09 16:28 ` [PATCH v4 2/8] KVM: nVMX: Handle dynamic MSR intercept toggling Vitaly Kuznetsov
2021-11-09 16:28 ` [PATCH v4 3/8] KVM: VMX: Macrofy the MSR bitmap getters and setters Vitaly Kuznetsov
2021-11-09 16:28 ` [PATCH v4 4/8] KVM: nVMX: Clean up x2APIC MSR handling for L2 Vitaly Kuznetsov
2021-11-09 16:28 ` [PATCH v4 5/8] KVM: nVMX: Don't use Enlightened MSR Bitmap for L3 Vitaly Kuznetsov
2021-11-09 16:28 ` Vitaly Kuznetsov [this message]
2021-11-09 16:28 ` [PATCH v4 7/8] KVM: nVMX: Track whether changes in L0 require MSR bitmap for L2 to be rebuilt Vitaly Kuznetsov
2021-11-09 16:28 ` [PATCH v4 8/8] KVM: nVMX: Implement Enlightened MSR Bitmap feature Vitaly Kuznetsov
2021-11-09 17:33 ` [PATCH v4 0/8] KVM: nVMX: Enlightened MSR Bitmap feature for Hyper-V on KVM (+ KVM: x86: MSR filtering and related fixes) Sean Christopherson
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