KVM: SVM: hyper-v: Remote TLB flush for SVM

Enable remote TLB flush for SVM.

Signed-off-by: Vineeth Pillai <viremana@linux.microsoft.com>
Message-Id: <1ee364e397e142aed662d2920d198cd03772f1a5.1622730232.git.viremana@linux.microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/svm/svm.c

@@ -43,6 +43,9 @@
 #include "svm.h"
 #include "svm_ops.h"
 
+#include "kvm_onhyperv.h"
+#include "svm_onhyperv.h"
+
 #define __ex(x) __kvm_handle_fault_on_reboot(x)
 
 MODULE_AUTHOR("Qumranet");
@@ -1003,6 +1006,8 @@ static __init int svm_hardware_setup(void)
 	/* Note, SEV setup consumes npt_enabled. */
 	sev_hardware_setup();
 
+	svm_hv_hardware_setup();
+
 	svm_adjust_mmio_mask();
 
 	for_each_possible_cpu(cpu) {
@@ -1296,6 +1301,8 @@ static void init_vmcb(struct kvm_vcpu *vcpu)
 		}
 	}
 
+	svm_hv_init_vmcb(svm->vmcb);
+
 	vmcb_mark_all_dirty(svm->vmcb);
 
 	enable_gif(svm);
@@ -3892,6 +3899,8 @@ static void svm_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa,
 		svm->vmcb->control.nested_cr3 = __sme_set(root_hpa);
 		vmcb_mark_dirty(svm->vmcb, VMCB_NPT);
 
+		hv_track_root_tdp(vcpu, root_hpa);
+
 		/* Loading L2's CR3 is handled by enter_svm_guest_mode.  */
 		if (!test_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail))
 			return;

arch/x86/kvm/svm/svm_onhyperv.h

@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * KVM L1 hypervisor optimizations on Hyper-V for SVM.
+ */
+
+#ifndef __ARCH_X86_KVM_SVM_ONHYPERV_H__
+#define __ARCH_X86_KVM_SVM_ONHYPERV_H__
+
+#if IS_ENABLED(CONFIG_HYPERV)
+#include <asm/mshyperv.h>
+
+#include "hyperv.h"
+#include "kvm_onhyperv.h"
+
+static struct kvm_x86_ops svm_x86_ops;
+
+/*
+ * Hyper-V uses the software reserved 32 bytes in VMCB
+ * control area to expose SVM enlightenments to guests.
+ */
+struct hv_enlightenments {
+	struct __packed hv_enlightenments_control {
+		u32 nested_flush_hypercall:1;
+		u32 msr_bitmap:1;
+		u32 enlightened_npt_tlb: 1;
+		u32 reserved:29;
+	} __packed hv_enlightenments_control;
+	u32 hv_vp_id;
+	u64 hv_vm_id;
+	u64 partition_assist_page;
+	u64 reserved;
+} __packed;
+
+static inline void svm_hv_init_vmcb(struct vmcb *vmcb)
+{
+	struct hv_enlightenments *hve =
+		(struct hv_enlightenments *)vmcb->control.reserved_sw;
+
+	if (npt_enabled &&
+	    ms_hyperv.nested_features & HV_X64_NESTED_ENLIGHTENED_TLB)
+		hve->hv_enlightenments_control.enlightened_npt_tlb = 1;
+}
+
+static inline void svm_hv_hardware_setup(void)
+{
+	if (npt_enabled &&
+	    ms_hyperv.nested_features & HV_X64_NESTED_ENLIGHTENED_TLB) {
+		pr_info("kvm: Hyper-V enlightened NPT TLB flush enabled\n");
+		svm_x86_ops.tlb_remote_flush = hv_remote_flush_tlb;
+		svm_x86_ops.tlb_remote_flush_with_range =
+				hv_remote_flush_tlb_with_range;
+	}
+}
+
+#else
+
+static inline void svm_hv_init_vmcb(struct vmcb *vmcb)
+{
+}
+
+static inline void svm_hv_hardware_setup(void)
+{
+}
+#endif /* CONFIG_HYPERV */
+
+#endif /* __ARCH_X86_KVM_SVM_ONHYPERV_H__ */