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Commit 8370c3d0 authored by Tom Lendacky's avatar Tom Lendacky Committed by Radim Krčmář
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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: default avatarTom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
Signed-off-by: default avatarBrijesh Singh <brijesh.singh@amd.com>
Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
parent 14727754

arch/x86/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

arch/x86/kvm/svm.c

+3 −2
Original line number Diff line number Diff line
@@ -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)

arch/x86/kvm/x86.c

+43 −0
Original line number Diff line number Diff line
@@ -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);