From 4e62aa96d6e55c1b2a4e841f1f8601eae81e81ae Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Fri, 30 Jul 2021 14:26:24 +0200 Subject: [PATCH] KVM: x86: hyper-v: Check if guest is allowed to use XMM registers for hypercall input MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit TLFS states that "Availability of the XMM fast hypercall interface is indicated via the “Hypervisor Feature Identification” CPUID Leaf (0x40000003, see section 2.4.4) ... Any attempt to use this interface when the hypervisor does not indicate availability will result in a #UD fault." Implement the check for 'strict' mode (KVM_CAP_HYPERV_ENFORCE_CPUID). Signed-off-by: Vitaly Kuznetsov Reviewed-by: Siddharth Chandrasekaran Signed-off-by: Paolo Bonzini Message-Id: <20210730122625.112848-4-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/hyperv.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 2945b93dbadd..0b38f944c6b6 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -2140,6 +2140,7 @@ static bool hv_check_hypercall_access(struct kvm_vcpu_hv *hv_vcpu, u16 code) int kvm_hv_hypercall(struct kvm_vcpu *vcpu) { + struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu); struct kvm_hv_hcall hc; u64 ret = HV_STATUS_SUCCESS; @@ -2177,13 +2178,21 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu) trace_kvm_hv_hypercall(hc.code, hc.fast, hc.rep_cnt, hc.rep_idx, hc.ingpa, hc.outgpa); - if (unlikely(!hv_check_hypercall_access(to_hv_vcpu(vcpu), hc.code))) { + if (unlikely(!hv_check_hypercall_access(hv_vcpu, hc.code))) { ret = HV_STATUS_ACCESS_DENIED; goto hypercall_complete; } - if (hc.fast && is_xmm_fast_hypercall(&hc)) + if (hc.fast && is_xmm_fast_hypercall(&hc)) { + if (unlikely(hv_vcpu->enforce_cpuid && + !(hv_vcpu->cpuid_cache.features_edx & + HV_X64_HYPERCALL_XMM_INPUT_AVAILABLE))) { + kvm_queue_exception(vcpu, UD_VECTOR); + return 1; + } + kvm_hv_hypercall_read_xmm(&hc); + } switch (hc.code) { case HVCALL_NOTIFY_LONG_SPIN_WAIT: -- 2.11.0