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Diffstat (limited to 'arch/x86/kvm/hyperv.c')
-rw-r--r--arch/x86/kvm/hyperv.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 421899f6ad7b..cc24b3a32c44 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1371,7 +1371,16 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *current_vcpu, u64 ingpa,
valid_bank_mask = BIT_ULL(0);
sparse_banks[0] = flush.processor_mask;
- all_cpus = flush.flags & HV_FLUSH_ALL_PROCESSORS;
+
+ /*
+ * Work around possible WS2012 bug: it sends hypercalls
+ * with processor_mask = 0x0 and HV_FLUSH_ALL_PROCESSORS clear,
+ * while also expecting us to flush something and crashing if
+ * we don't. Let's treat processor_mask == 0 same as
+ * HV_FLUSH_ALL_PROCESSORS.
+ */
+ all_cpus = (flush.flags & HV_FLUSH_ALL_PROCESSORS) ||
+ flush.processor_mask == 0;
} else {
if (unlikely(kvm_read_guest(kvm, ingpa, &flush_ex,
sizeof(flush_ex))))