kvm: svm: Add kvm_fast_pio_in support

Update the I/O interception support to add the kvm_fast_pio_in function
to speed up the in instruction similar to the out instruction.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index da07e175dac87b37c4b98f5b005d6fbe0f124d53..77cb3f93de2b02c495dd9b08a4d0752fe0a1ee70 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1133,6 +1133,7 @@ int kvm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr);
 struct x86_emulate_ctxt;
 
 int kvm_fast_pio_out(struct kvm_vcpu *vcpu, int size, unsigned short port);
+int kvm_fast_pio_in(struct kvm_vcpu *vcpu, int size, unsigned short port);
 void kvm_emulate_cpuid(struct kvm_vcpu *vcpu);
 int kvm_emulate_halt(struct kvm_vcpu *vcpu);
 int kvm_vcpu_halt(struct kvm_vcpu *vcpu);

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 4e462bb857230def837d60a7dd045a858576f143..5e64e656103c1fd667254b814b177fc083bb82b2 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2270,7 +2270,7 @@ static int io_interception(struct vcpu_svm *svm)
        ++svm->vcpu.stat.io_exits;
        string = (io_info & SVM_IOIO_STR_MASK) != 0;
        in = (io_info & SVM_IOIO_TYPE_MASK) != 0;
-       if (string || in)
+       if (string)
                return emulate_instruction(vcpu, 0) == EMULATE_DONE;
 
        port = io_info >> 16;
@@ -2278,7 +2278,8 @@ static int io_interception(struct vcpu_svm *svm)
        svm->next_rip = svm->vmcb->control.exit_info_2;
        skip_emulated_instruction(&svm->vcpu);
 
-       return kvm_fast_pio_out(vcpu, size, port);
+       return in ? kvm_fast_pio_in(vcpu, size, port)
+                 : kvm_fast_pio_out(vcpu, size, port);
 }
 
 static int nmi_interception(struct vcpu_svm *svm)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6f9c9ad13f88e0c735c474f7f8f779231ff87297..ec59301f51926a06aa3f8f57c08e112362b1bda3 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5615,6 +5615,49 @@ int kvm_fast_pio_out(struct kvm_vcpu *vcpu, int size, unsigned short port)
 }
 EXPORT_SYMBOL_GPL(kvm_fast_pio_out);
 
+static int complete_fast_pio_in(struct kvm_vcpu *vcpu)
+{
+       unsigned long val;
+
+       /* We should only ever be called with arch.pio.count equal to 1 */
+       BUG_ON(vcpu->arch.pio.count != 1);
+
+       /* For size less than 4 we merge, else we zero extend */
+       val = (vcpu->arch.pio.size < 4) ? kvm_register_read(vcpu, VCPU_REGS_RAX)
+                                       : 0;
+
+       /*
+        * Since vcpu->arch.pio.count == 1 let emulator_pio_in_emulated perform
+        * the copy and tracing
+        */
+       emulator_pio_in_emulated(&vcpu->arch.emulate_ctxt, vcpu->arch.pio.size,
+                                vcpu->arch.pio.port, &val, 1);
+       kvm_register_write(vcpu, VCPU_REGS_RAX, val);
+
+       return 1;
+}
+
+int kvm_fast_pio_in(struct kvm_vcpu *vcpu, int size, unsigned short port)
+{
+       unsigned long val;
+       int ret;
+
+       /* For size less than 4 we merge, else we zero extend */
+       val = (size < 4) ? kvm_register_read(vcpu, VCPU_REGS_RAX) : 0;
+
+       ret = emulator_pio_in_emulated(&vcpu->arch.emulate_ctxt, size, port,
+                                      &val, 1);
+       if (ret) {
+               kvm_register_write(vcpu, VCPU_REGS_RAX, val);
+               return ret;
+       }
+
+       vcpu->arch.complete_userspace_io = complete_fast_pio_in;
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_fast_pio_in);
+
 static int kvmclock_cpu_down_prep(unsigned int cpu)
 {
        __this_cpu_write(cpu_tsc_khz, 0);