KVM: SVM: hyper-v: Enlightened MSR-Bitmap support

Enlightened MSR-Bitmap as per TLFS:

 "The L1 hypervisor may collaborate with the L0 hypervisor to make MSR
  accesses more efficient. It can enable enlightened MSR bitmaps by setting
  the corresponding field in the enlightened VMCS to 1. When enabled, L0
  hypervisor does not monitor the MSR bitmaps for changes. Instead, the L1
  hypervisor must invalidate the corresponding clean field after making
  changes to one of the MSR bitmaps."

Enable this for SVM.

Related VMX changes:
commit ceef7d10dfb6 ("KVM: x86: VMX: hyper-v: Enlightened MSR-Bitmap support")

Signed-off-by: Vineeth Pillai <viremana@linux.microsoft.com>
Message-Id: <87df0710f95d28b91cc4ea014fc4d71056eebbee.1622730232.git.viremana@linux.microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 4d7b67c78a8997325b69efa8b01b6a928c4f844d..1b0056ef36af657fbbf38410ee11833eddbd7f89 100644 (file)
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -683,6 +683,9 @@ static void set_msr_interception_bitmap(struct kvm_vcpu *vcpu, u32 *msrpm,
        write ? clear_bit(bit_write, &tmp) : set_bit(bit_write, &tmp);
 
        msrpm[offset] = tmp;
+
+       svm_hv_vmcb_dirty_nested_enlightenments(vcpu);
+
 }
 
 void set_msr_interception(struct kvm_vcpu *vcpu, u32 *msrpm, u32 msr,

diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index af09bcd229bdb191cd514b0ee2bce9bb592c2fdb..670f0c0ed73bc59c139466b0c89bd43307e779dd 100644 (file)
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -254,6 +254,11 @@ static inline void vmcb_mark_all_clean(struct vmcb *vmcb)
                               & ~VMCB_ALWAYS_DIRTY_MASK;
 }
 
+static inline bool vmcb_is_clean(struct vmcb *vmcb, int bit)
+{
+       return (vmcb->control.clean & (1 << bit));
+}
+
 static inline void vmcb_mark_dirty(struct vmcb *vmcb, int bit)
 {
        vmcb->control.clean &= ~(1 << bit);

diff --git a/arch/x86/kvm/svm/svm_onhyperv.h b/arch/x86/kvm/svm/svm_onhyperv.h
index 57291e22239569abe136da6291246f017c7f2bef..0f262460b2e68c47734b068b1c6d72f260458c93 100644 (file)
--- a/arch/x86/kvm/svm/svm_onhyperv.h
+++ b/arch/x86/kvm/svm/svm_onhyperv.h
@@ -31,6 +31,11 @@ struct hv_enlightenments {
        u64 reserved;
 } __packed;
 
+/*
+ * Hyper-V uses the software reserved clean bit in VMCB
+ */
+#define VMCB_HV_NESTED_ENLIGHTENMENTS VMCB_SW
+
 static inline void svm_hv_init_vmcb(struct vmcb *vmcb)
 {
        struct hv_enlightenments *hve =
@@ -52,6 +57,23 @@ static inline void svm_hv_hardware_setup(void)
        }
 }
 
+static inline void svm_hv_vmcb_dirty_nested_enlightenments(
+               struct kvm_vcpu *vcpu)
+{
+       struct vmcb *vmcb = to_svm(vcpu)->vmcb;
+       struct hv_enlightenments *hve =
+               (struct hv_enlightenments *)vmcb->control.reserved_sw;
+
+       /*
+        * vmcb can be NULL if called during early vcpu init.
+        * And its okay not to mark vmcb dirty during vcpu init
+        * as we mark it dirty unconditionally towards end of vcpu
+        * init phase.
+        */
+       if (vmcb && vmcb_is_clean(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS) &&
+           hve->hv_enlightenments_control.msr_bitmap)
+               vmcb_mark_dirty(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS);
+}
 #else
 
 static inline void svm_hv_init_vmcb(struct vmcb *vmcb)
@@ -61,6 +83,11 @@ static inline void svm_hv_init_vmcb(struct vmcb *vmcb)
 static inline void svm_hv_hardware_setup(void)
 {
 }
+
+static inline void svm_hv_vmcb_dirty_nested_enlightenments(
+               struct kvm_vcpu *vcpu)
+{
+}
 #endif /* CONFIG_HYPERV */
 
 #endif /* __ARCH_X86_KVM_SVM_ONHYPERV_H__ */