x86/kvm/hyperv: don't clear VP assist pages on init (12e0c618) · Commits · 戴 / test

VP assist pages may hold valuable data which needs to be preserved across migration. Clean PV EOI portion of the data on init, the guest is responsible for making sure there's no garbage in the rest. This will be used for nVMX migration, eVMCS address needs to be preserved. Signed-off-by:

Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/hyperv.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -1104,7 +1104,13 @@ static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
		addr = kvm_vcpu_gfn_to_hva(vcpu, gfn);
		if (kvm_is_error_hva(addr))
		return 1;
		if (__clear_user((void __user *)addr, PAGE_SIZE))

		/*
		* Clear apic_assist portion of f(struct hv_vp_assist_page
		* only, there can be valuable data in the rest which needs
		* to be preserved e.g. on migration.
		*/
		if (__clear_user((void __user *)addr, sizeof(u32)))
		return 1;
		hv_vcpu->hv_vapic = data;
		kvm_vcpu_mark_page_dirty(vcpu, gfn);

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