summaryrefslogtreecommitdiff
path: root/arch/x86
diff options
context:
space:
mode:
authorVitaly Kuznetsov <vkuznets@redhat.com>2018-03-01 15:15:14 +0100
committerPaolo Bonzini <pbonzini@redhat.com>2018-03-16 22:01:33 +0100
commit915e6f78bd0641da692ffa7e0b766e633e12e628 (patch)
treec5a86f11dcaeec6197b4a5d5ee6333d4138d6851 /arch/x86
parent98f65ad458441ea3a243395345811132ee850093 (diff)
x86/kvm/hyper-v: inject #GP only when invalid SINTx vector is unmasked
Hyper-V 2016 on KVM with SynIC enabled doesn't boot with the following trace: kvm_entry: vcpu 0 kvm_exit: reason MSR_WRITE rip 0xfffff8000131c1e5 info 0 0 kvm_hv_synic_set_msr: vcpu_id 0 msr 0x40000090 data 0x10000 host 0 kvm_msr: msr_write 40000090 = 0x10000 (#GP) kvm_inj_exception: #GP (0x0) KVM acts according to the following statement from TLFS: " 11.8.4 SINTx Registers ... Valid values for vector are 16-255 inclusive. Specifying an invalid vector number results in #GP. " However, I checked and genuine Hyper-V doesn't #GP when we write 0x10000 to SINTx. I checked with Microsoft and they confirmed that if either the Masked bit (bit 16) or the Polling bit (bit 18) is set to 1, then they ignore the value of Vector. Make KVM act accordingly. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Roman Kagan <rkagan@virtuozzo.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kvm/hyperv.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 93a22748c32b..9225b3a64579 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -96,9 +96,17 @@ static int synic_set_sint(struct kvm_vcpu_hv_synic *synic, int sint,
u64 data, bool host)
{
int vector, old_vector;
+ bool masked;
vector = data & HV_SYNIC_SINT_VECTOR_MASK;
- if (vector < HV_SYNIC_FIRST_VALID_VECTOR && !host)
+ masked = data & HV_SYNIC_SINT_MASKED;
+
+ /*
+ * Valid vectors are 16-255, however, nested Hyper-V attempts to write
+ * default '0x10000' value on boot and this should not #GP. We need to
+ * allow zero-initing the register from host as well.
+ */
+ if (vector < HV_SYNIC_FIRST_VALID_VECTOR && !host && !masked)
return 1;
/*
* Guest may configure multiple SINTs to use the same vector, so