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Diffstat (limited to 'arch/x86/kvm/x86.c')
-rw-r--r--arch/x86/kvm/x86.c21
1 files changed, 19 insertions, 2 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4a61e1609c97..f3337adaf9b3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6328,6 +6328,12 @@ int kvm_emulate_instruction_from_buffer(struct kvm_vcpu *vcpu,
}
EXPORT_SYMBOL_GPL(kvm_emulate_instruction_from_buffer);
+static int complete_fast_pio_out_port_0x7e(struct kvm_vcpu *vcpu)
+{
+ vcpu->arch.pio.count = 0;
+ return 1;
+}
+
static int complete_fast_pio_out(struct kvm_vcpu *vcpu)
{
vcpu->arch.pio.count = 0;
@@ -6344,12 +6350,23 @@ static int kvm_fast_pio_out(struct kvm_vcpu *vcpu, int size,
unsigned long val = kvm_register_read(vcpu, VCPU_REGS_RAX);
int ret = emulator_pio_out_emulated(&vcpu->arch.emulate_ctxt,
size, port, &val, 1);
+ if (ret)
+ return ret;
- if (!ret) {
+ /*
+ * Workaround userspace that relies on old KVM behavior of %rip being
+ * incremented prior to exiting to userspace to handle "OUT 0x7e".
+ */
+ if (port == 0x7e &&
+ kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_OUT_7E_INC_RIP)) {
+ vcpu->arch.complete_userspace_io =
+ complete_fast_pio_out_port_0x7e;
+ kvm_skip_emulated_instruction(vcpu);
+ } else {
vcpu->arch.pio.linear_rip = kvm_get_linear_rip(vcpu);
vcpu->arch.complete_userspace_io = complete_fast_pio_out;
}
- return ret;
+ return 0;
}
static int complete_fast_pio_in(struct kvm_vcpu *vcpu)