From 12e0c6186ba44bb6194cf5d2eda8f46880126587 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Tue, 16 Oct 2018 18:50:05 +0200 Subject: x86/kvm/hyperv: don't clear VP assist pages on init 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 Signed-off-by: Paolo Bonzini --- arch/x86/kvm/hyperv.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index d9b7b4cd4e43..4e80080f277a 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -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); -- cgit v1.2.3-59-g8ed1b