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| author | Jon Doron <arilou@gmail.com> | 2020-05-29 16:45:41 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-06-01 04:26:11 -0400 |
| commit | 45c38973ed1868b8448079edd48bf24ab8b326fa (patch) | |
| tree | e080322f6dbae4ee754b763a4b505b2c14fa37c5 /arch/x86/kvm | |
| parent | f97f5a56f5977311f3833056a73cdbb0ee56cb1e (diff) | |
| download | linux-45c38973ed1868b8448079edd48bf24ab8b326fa.tar.gz | |
x86/kvm/hyper-v: enable hypercalls regardless of hypercall page
Microsoft's kdvm.dll dbgtransport module does not respect the hypercall page and simply identifies the CPU being used (AMD/Intel) and according to it simply makes hypercalls with the relevant instruction (vmmcall/vmcall respectively). The relevant function in kdvm is KdHvConnectHypervisor which first checks if the hypercall page has been enabled via HV_X64_MSR_HYPERCALL_ENABLE, and in case it was not it simply sets the HV_X64_MSR_GUEST_OS_ID to 0x1000101010001 which means: build_number = 0x0001 service_version = 0x01 minor_version = 0x01 major_version = 0x01 os_id = 0x00 (Undefined) vendor_id = 1 (Microsoft) os_type = 0 (A value of 0 indicates a proprietary, closed source OS) and starts issuing the hypercall without setting the hypercall page. To resolve this issue simply enable hypercalls also if the guest_os_id is not 0. Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Jon Doron <arilou@gmail.com> Message-Id: <20200529134543.1127440-5-arilou@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/hyperv.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index c21f99357ad5..2fb1464a483f 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1656,7 +1656,7 @@ ret_success: bool kvm_hv_hypercall_enabled(struct kvm *kvm) { - return READ_ONCE(kvm->arch.hyperv.hv_hypercall) & HV_X64_MSR_HYPERCALL_ENABLE; + return READ_ONCE(kvm->arch.hyperv.hv_guest_os_id) != 0; } static void kvm_hv_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result) |