KVM: SVM: Optimize nested svm msrpm merging (323c3d80) · Commits · 戴 / test

arch/x86/kvm/svm.c

+71 −9

Original line number	Diff line number	Diff line
		@@ -93,6 +93,9 @@ struct nested_state {

		};

		#define MSRPM_OFFSETS 16
		static u32 msrpm_offsets[MSRPM_OFFSETS] __read_mostly;

		struct vcpu_svm {
		struct kvm_vcpu vcpu;
		struct vmcb *vmcb;
		@@ -510,6 +513,49 @@ static void svm_vcpu_init_msrpm(u32 *msrpm)
		}
		}

		static void add_msr_offset(u32 offset)
		{
		int i;

		for (i = 0; i < MSRPM_OFFSETS; ++i) {

		/* Offset already in list? */
		if (msrpm_offsets[i] == offset)
		return;

		/* Slot used by another offset? */
		if (msrpm_offsets[i] != MSR_INVALID)
		continue;

		/* Add offset to list */
		msrpm_offsets[i] = offset;

		return;
		}

		/*
		* If this BUG triggers the msrpm_offsets table has an overflow. Just
		* increase MSRPM_OFFSETS in this case.
		*/
		BUG();
		}

		static void init_msrpm_offsets(void)
		{
		int i;

		memset(msrpm_offsets, 0xff, sizeof(msrpm_offsets));

		for (i = 0; direct_access_msrs[i].index != MSR_INVALID; i++) {
		u32 offset;

		offset = svm_msrpm_offset(direct_access_msrs[i].index);
		BUG_ON(offset == MSR_INVALID);

		add_msr_offset(offset);
		}
		}

		static void svm_enable_lbrv(struct vcpu_svm *svm)
		{
		u32 *msrpm = svm->msrpm;
		@@ -548,6 +594,8 @@ static __init int svm_hardware_setup(void)
		memset(iopm_va, 0xff, PAGE_SIZE * (1 << IOPM_ALLOC_ORDER));
		iopm_base = page_to_pfn(iopm_pages) << PAGE_SHIFT;

		init_msrpm_offsets();

		if (boot_cpu_has(X86_FEATURE_NX))
		kvm_enable_efer_bits(EFER_NX);

		@@ -811,6 +859,7 @@ static struct kvm_vcpu svm_create_vcpu(struct kvm kvm, unsigned int id)
		svm_vcpu_init_msrpm(svm->msrpm);

		svm->nested.msrpm = page_address(nested_msrpm_pages);
		svm_vcpu_init_msrpm(svm->nested.msrpm);

		svm->vmcb = page_address(page);
		clear_page(svm->vmcb);
		@@ -1888,21 +1937,34 @@ static int nested_svm_vmexit(struct vcpu_svm *svm)

		static bool nested_svm_vmrun_msrpm(struct vcpu_svm *svm)
		{
		u32 *nested_msrpm;
		struct page *page;
		/*
		* This function merges the msr permission bitmaps of kvm and the
		* nested vmcb. It is omptimized in that it only merges the parts where
		* the kvm msr permission bitmap may contain zero bits
		*/
		int i;

		nested_msrpm = nested_svm_map(svm, svm->nested.vmcb_msrpm, &page);
		if (!nested_msrpm)
		if (!(svm->nested.intercept & (1ULL << INTERCEPT_MSR_PROT)))
		return true;

		for (i = 0; i < MSRPM_OFFSETS; i++) {
		u32 value, p;
		u64 offset;

		if (msrpm_offsets[i] == 0xffffffff)
		break;

		offset = svm->nested.vmcb_msrpm + msrpm_offsets[i];
		p = msrpm_offsets[i] / 4;

		if (kvm_read_guest(svm->vcpu.kvm, offset, &value, 4))
		return false;

		for (i = 0; i < PAGE_SIZE * (1 << MSRPM_ALLOC_ORDER) / 4; i++)
		svm->nested.msrpm[i] = svm->msrpm[i] \| nested_msrpm[i];
		svm->nested.msrpm[p] = svm->msrpm[p] \| value;
		}

		svm->vmcb->control.msrpm_base_pa = __pa(svm->nested.msrpm);

		nested_svm_unmap(page);

		return true;
		}

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