[PATCH v2 0/8] KVM: x86: vcpu->arch.pio* cleanups

[PATCH v2 0/8] KVM: x86: vcpu->arch.pio* cleanups

[Paolo Bonzini]

These patches complete the job started by commit 3b27de271839 ("KVM:
x86: split the two parts of emulator_pio_in", 2021-10-22).  The commit
message eloquently said that emulator_pio_in_out "currently hardcodes
vcpu->arch.pio_data as the source/destination buffer, which sucks but
will be fixed after the more severe SEV-ES buffer overflow".  Some time
has passed and it's high time to do it.

After this series, in-kernel PIO does not use vcpu->arch.pio* anymore;
it is only used by complete_emulator_pio_in.

Paolo

v1->v2:
- split out "KVM: x86: complete fast IN directly with complete_emulator_pio_in()"
- remove WARN if emulated PIO performs successful in-kernel iterations before
  falling back to userspace, it is (unfortunately) valid if SRCU changes mid-loop.
- new patch 3 to handle unregistered devices mid-loop, dropping writes and reading
  as zero
- WARN if non-NULL data is passed to emulator_pio_in_out() before the code is
  ready to handle in-kernel PIO without vcpu->arch.pio*
- use "size" in SEV case instead of vcpu->arch.pio_size

Paolo Bonzini (8):
  KVM: x86: complete fast IN directly with complete_emulator_pio_in()
  KVM: x86: inline kernel_pio into its sole caller
  KVM: x86: drop PIO from unregistered devices
  KVM: x86: move all vcpu->arch.pio* setup in emulator_pio_in_out()
  KVM: x86: wean in-kernel PIO from vcpu->arch.pio*
  KVM: x86: wean fast IN from emulator_pio_in
  KVM: x86: de-underscorify __emulator_pio_in
  KVM: SEV-ES: reuse advance_sev_es_emulated_ins for OUT too

 arch/x86/kvm/trace.h |   2 +-
 arch/x86/kvm/x86.c   | 133 ++++++++++++++++++++-----------------------
 2 files changed, 62 insertions(+), 73 deletions(-)

-- 
2.31.1

[PATCH v2 1/8] KVM: x86: complete fast IN directly with complete_emulator_pio_in()

[Paolo Bonzini]

Use complete_emulator_pio_in() directly when completing fast PIO, there's
no need to bounce through emulator_pio_in(): the comment about ECX
changing doesn't apply to fast PIO, which isn't used for string I/O.

No functional change intended.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/x86/kvm/x86.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d88600e41ff8..d66a873f4427 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8871,11 +8871,7 @@ static int complete_fast_pio_in(struct kvm_vcpu *vcpu)
 	/* For size less than 4 we merge, else we zero extend */
 	val = (vcpu->arch.pio.size < 4) ? kvm_rax_read(vcpu) : 0;
 
-	/*
-	 * Since vcpu->arch.pio.count == 1 let emulator_pio_in perform
-	 * the copy and tracing
-	 */
-	emulator_pio_in(vcpu, vcpu->arch.pio.size, vcpu->arch.pio.port, &val, 1);
+	complete_emulator_pio_in(vcpu, &val);
 	kvm_rax_write(vcpu, val);
 
 	return kvm_skip_emulated_instruction(vcpu);
-- 
2.31.1

[PATCH v2 2/8] KVM: x86: inline kernel_pio into its sole caller

[Paolo Bonzini]

The caller of kernel_pio already has arguments for most of what kernel_pio
fishes out of vcpu->arch.pio.  This is the first step towards ensuring that
vcpu->arch.pio.* is only used when exiting to userspace.

No functional change intended.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/x86/kvm/x86.c | 38 ++++++++++++++++----------------------
 1 file changed, 16 insertions(+), 22 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d66a873f4427..524a96d26399 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7575,37 +7575,31 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt,
 	return emulator_write_emulated(ctxt, addr, new, bytes, exception);
 }
 
-static int kernel_pio(struct kvm_vcpu *vcpu, void *pd)
-{
-	int r = 0, i;
-
-	for (i = 0; i < vcpu->arch.pio.count; i++) {
-		if (vcpu->arch.pio.in)
-			r = kvm_io_bus_read(vcpu, KVM_PIO_BUS, vcpu->arch.pio.port,
-					    vcpu->arch.pio.size, pd);
-		else
-			r = kvm_io_bus_write(vcpu, KVM_PIO_BUS,
-					     vcpu->arch.pio.port, vcpu->arch.pio.size,
-					     pd);
-		if (r)
-			break;
-		pd += vcpu->arch.pio.size;
-	}
-	return r;
-}
-
 static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size,
 			       unsigned short port,
 			       unsigned int count, bool in)
 {
+	void *data = vcpu->arch.pio_data;
+	unsigned i;
+	int r;
+
 	vcpu->arch.pio.port = port;
 	vcpu->arch.pio.in = in;
-	vcpu->arch.pio.count  = count;
+	vcpu->arch.pio.count = count;
 	vcpu->arch.pio.size = size;
 
-	if (!kernel_pio(vcpu, vcpu->arch.pio_data))
-		return 1;
+	for (i = 0; i < count; i++) {
+		if (in)
+			r = kvm_io_bus_read(vcpu, KVM_PIO_BUS, port, size, data);
+		else
+			r = kvm_io_bus_write(vcpu, KVM_PIO_BUS, port, size, data);
+		if (r)
+			goto userspace_io;
+		data += size;
+	}
+	return 1;
 
+userspace_io:
 	vcpu->run->exit_reason = KVM_EXIT_IO;
 	vcpu->run->io.direction = in ? KVM_EXIT_IO_IN : KVM_EXIT_IO_OUT;
 	vcpu->run->io.size = size;
-- 
2.31.1

[PATCH v2 3/8] KVM: x86: drop PIO from unregistered devices

[Paolo Bonzini]

KVM protects the device list with SRCU, and therefore different calls
to kvm_io_bus_read()/kvm_io_bus_write() can very well see different
incarnations of kvm->buses.  If userspace unregisters a device while
vCPUs are running there is no well-defined result.  This patch applies
a safe fallback by returning early from emulator_pio_in_out().  This
corresponds to returning zeroes from IN, and dropping the writes on
the floor for OUT.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/x86/kvm/x86.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 524a96d26399..5a56d39bd81f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7593,8 +7593,19 @@ static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size,
 			r = kvm_io_bus_read(vcpu, KVM_PIO_BUS, port, size, data);
 		else
 			r = kvm_io_bus_write(vcpu, KVM_PIO_BUS, port, size, data);
-		if (r)
-			goto userspace_io;
+
+		if (r) {
+			if (i == 0)
+				goto userspace_io;
+
+			/*
+			 * Userspace must have unregistered the device while PIO
+			 * was running.  Drop writes / read as 0 (the buffer
+			 * was zeroed in __emulator_pio_in).
+			 */
+			break;
+		}
+
 		data += size;
 	}
 	return 1;
@@ -7606,7 +7617,6 @@ static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size,
 	vcpu->run->io.data_offset = KVM_PIO_PAGE_OFFSET * PAGE_SIZE;
 	vcpu->run->io.count = count;
 	vcpu->run->io.port = port;
-
 	return 0;
 }
 
-- 
2.31.1

[PATCH v2 4/8] KVM: x86: move all vcpu->arch.pio* setup in emulator_pio_in_out()

[Paolo Bonzini]

For now, this is basically an excuse to add back the void* argument to
the function, while removing some knowledge of vcpu->arch.pio* from
its callers.  The WARN that vcpu->arch.pio.count is zero is also
extended to OUT operations.

The vcpu->arch.pio* fields still need to be filled even when the PIO is
handled in-kernel as __emulator_pio_in() is always followed by
complete_emulator_pio_in().  But after fixing that, it will be possible to
to only populate the vcpu->arch.pio* fields on userspace exits.

No functional change intended.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/x86/kvm/trace.h |  2 +-
 arch/x86/kvm/x86.c   | 21 +++++++++++++--------
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index bc85622e28b2..2120d7c060a9 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -154,7 +154,7 @@ TRACE_EVENT(kvm_xen_hypercall,
 
 TRACE_EVENT(kvm_pio,
 	TP_PROTO(unsigned int rw, unsigned int port, unsigned int size,
-		 unsigned int count, void *data),
+		 unsigned int count, const void *data),
 	TP_ARGS(rw, port, size, count, data),
 
 	TP_STRUCT__entry(
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5a56d39bd81f..368d0d4d56ff 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7576,17 +7576,25 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt,
 }
 
 static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size,
-			       unsigned short port,
+			       unsigned short port, void *data,
 			       unsigned int count, bool in)
 {
-	void *data = vcpu->arch.pio_data;
 	unsigned i;
 	int r;
 
+	WARN_ON_ONCE(vcpu->arch.pio.count);
 	vcpu->arch.pio.port = port;
 	vcpu->arch.pio.in = in;
 	vcpu->arch.pio.count = count;
 	vcpu->arch.pio.size = size;
+	if (in) {
+		/* The buffer is only used in complete_emulator_pio_in().  */
+		WARN_ON(data);
+		memset(vcpu->arch.pio_data, 0, size * count);
+	} else {
+		memcpy(vcpu->arch.pio_data, data, size * count);
+	}
+	data = vcpu->arch.pio_data;
 
 	for (i = 0; i < count; i++) {
 		if (in)
@@ -7623,9 +7631,7 @@ static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size,
 static int __emulator_pio_in(struct kvm_vcpu *vcpu, int size,
 			     unsigned short port, unsigned int count)
 {
-	WARN_ON(vcpu->arch.pio.count);
-	memset(vcpu->arch.pio_data, 0, size * count);
-	return emulator_pio_in_out(vcpu, size, port, count, true);
+	return emulator_pio_in_out(vcpu, size, port, NULL, count, true);
 }
 
 static void complete_emulator_pio_in(struct kvm_vcpu *vcpu, void *val)
@@ -7674,9 +7680,8 @@ static int emulator_pio_out(struct kvm_vcpu *vcpu, int size,
 {
 	int ret;
 
-	memcpy(vcpu->arch.pio_data, val, size * count);
-	trace_kvm_pio(KVM_PIO_OUT, port, size, count, vcpu->arch.pio_data);
-	ret = emulator_pio_in_out(vcpu, size, port, count, false);
+	trace_kvm_pio(KVM_PIO_OUT, port, size, count, val);
+	ret = emulator_pio_in_out(vcpu, size, port, (void *)val, count, false);
 	if (ret)
                 vcpu->arch.pio.count = 0;
 
-- 
2.31.1

[PATCH v2 5/8] KVM: x86: wean in-kernel PIO from vcpu->arch.pio*

[Paolo Bonzini]

Make emulator_pio_in_out operate directly on the provided buffer
as long as PIO is handled inside KVM.

For input operations, this means that, in the case of in-kernel
PIO, __emulator_pio_in() does not have to be always followed
by complete_emulator_pio_in().  This affects emulator_pio_in() and
kvm_sev_es_ins(); for the latter, that is why the call moves from
advance_sev_es_emulated_ins() to complete_sev_es_emulated_ins().

For output, it means that vcpu->pio.count is never set unnecessarily
and there is no need to clear it; but also vcpu->pio.size must not
be used in kvm_sev_es_outs(), because it will not be updated for
in-kernel OUT.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/x86/kvm/x86.c | 73 ++++++++++++++++++++--------------------------
 1 file changed, 32 insertions(+), 41 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 368d0d4d56ff..716ae5c92687 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7583,19 +7583,6 @@ static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size,
 	int r;
 
 	WARN_ON_ONCE(vcpu->arch.pio.count);
-	vcpu->arch.pio.port = port;
-	vcpu->arch.pio.in = in;
-	vcpu->arch.pio.count = count;
-	vcpu->arch.pio.size = size;
-	if (in) {
-		/* The buffer is only used in complete_emulator_pio_in().  */
-		WARN_ON(data);
-		memset(vcpu->arch.pio_data, 0, size * count);
-	} else {
-		memcpy(vcpu->arch.pio_data, data, size * count);
-	}
-	data = vcpu->arch.pio_data;
-
 	for (i = 0; i < count; i++) {
 		if (in)
 			r = kvm_io_bus_read(vcpu, KVM_PIO_BUS, port, size, data);
@@ -7608,9 +7595,10 @@ static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size,
 
 			/*
 			 * Userspace must have unregistered the device while PIO
-			 * was running.  Drop writes / read as 0 (the buffer
-			 * was zeroed in __emulator_pio_in).
+			 * was running.  Drop writes / read as 0.
 			 */
+			if (in)
+				memset(data, 0, size * (count - i));
 			break;
 		}
 
@@ -7619,6 +7607,16 @@ static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size,
 	return 1;
 
 userspace_io:
+	vcpu->arch.pio.port = port;
+	vcpu->arch.pio.in = in;
+	vcpu->arch.pio.count = count;
+	vcpu->arch.pio.size = size;
+
+	if (in)
+		memset(vcpu->arch.pio_data, 0, size * count);
+	else
+		memcpy(vcpu->arch.pio_data, data, size * count);
+
 	vcpu->run->exit_reason = KVM_EXIT_IO;
 	vcpu->run->io.direction = in ? KVM_EXIT_IO_IN : KVM_EXIT_IO_OUT;
 	vcpu->run->io.size = size;
@@ -7629,15 +7627,19 @@ static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size,
 }
 
 static int __emulator_pio_in(struct kvm_vcpu *vcpu, int size,
-			     unsigned short port, unsigned int count)
+			     unsigned short port, void *val, unsigned int count)
 {
-	return emulator_pio_in_out(vcpu, size, port, NULL, count, true);
+	int r = emulator_pio_in_out(vcpu, size, port, val, count, true);
+	if (r)
+		trace_kvm_pio(KVM_PIO_IN, port, size, count, val);
+
+	return r;
 }
 
 static void complete_emulator_pio_in(struct kvm_vcpu *vcpu, void *val)
 {
 	int size = vcpu->arch.pio.size;
-	unsigned count = vcpu->arch.pio.count;
+	unsigned int count = vcpu->arch.pio.count;
 	memcpy(val, vcpu->arch.pio_data, size * count);
 	trace_kvm_pio(KVM_PIO_IN, vcpu->arch.pio.port, size, count, vcpu->arch.pio_data);
 	vcpu->arch.pio.count = 0;
@@ -7654,16 +7656,11 @@ static int emulator_pio_in(struct kvm_vcpu *vcpu, int size,
 		 * shenanigans as KVM doesn't support modifying the rep count,
 		 * and the emulator ensures @count doesn't overflow the buffer.
 		 */
-	} else {
-		int r = __emulator_pio_in(vcpu, size, port, count);
-		if (!r)
-			return r;
-
-		/* Results already available, fall through.  */
+		complete_emulator_pio_in(vcpu, val);
+		return 1;
 	}
 
-	complete_emulator_pio_in(vcpu, val);
-	return 1;
+	return __emulator_pio_in(vcpu, size, port, val, count);
 }
 
 static int emulator_pio_in_emulated(struct x86_emulate_ctxt *ctxt,
@@ -7678,14 +7675,8 @@ static int emulator_pio_out(struct kvm_vcpu *vcpu, int size,
 			    unsigned short port, const void *val,
 			    unsigned int count)
 {
-	int ret;
-
 	trace_kvm_pio(KVM_PIO_OUT, port, size, count, val);
-	ret = emulator_pio_in_out(vcpu, size, port, (void *)val, count, false);
-	if (ret)
-                vcpu->arch.pio.count = 0;
-
-        return ret;
+	return emulator_pio_in_out(vcpu, size, port, (void *)val, count, false);
 }
 
 static int emulator_pio_out_emulated(struct x86_emulate_ctxt *ctxt,
@@ -13245,7 +13236,7 @@ static int kvm_sev_es_outs(struct kvm_vcpu *vcpu, unsigned int size,
 
 		/* memcpy done already by emulator_pio_out.  */
 		vcpu->arch.sev_pio_count -= count;
-		vcpu->arch.sev_pio_data += count * vcpu->arch.pio.size;
+		vcpu->arch.sev_pio_data += count * size;
 		if (!ret)
 			break;
 
@@ -13261,20 +13252,20 @@ static int kvm_sev_es_outs(struct kvm_vcpu *vcpu, unsigned int size,
 static int kvm_sev_es_ins(struct kvm_vcpu *vcpu, unsigned int size,
 			  unsigned int port);
 
-static void advance_sev_es_emulated_ins(struct kvm_vcpu *vcpu)
+static void advance_sev_es_emulated_ins(struct kvm_vcpu *vcpu, unsigned count, int size)
 {
-	unsigned count = vcpu->arch.pio.count;
-	complete_emulator_pio_in(vcpu, vcpu->arch.sev_pio_data);
 	vcpu->arch.sev_pio_count -= count;
-	vcpu->arch.sev_pio_data += count * vcpu->arch.pio.size;
+	vcpu->arch.sev_pio_data += count * size;
 }
 
 static int complete_sev_es_emulated_ins(struct kvm_vcpu *vcpu)
 {
+	unsigned count = vcpu->arch.pio.count;
 	int size = vcpu->arch.pio.size;
 	int port = vcpu->arch.pio.port;
 
-	advance_sev_es_emulated_ins(vcpu);
+	complete_emulator_pio_in(vcpu, vcpu->arch.sev_pio_data);
+	advance_sev_es_emulated_ins(vcpu, count, size);
 	if (vcpu->arch.sev_pio_count)
 		return kvm_sev_es_ins(vcpu, size, port);
 	return 1;
@@ -13286,11 +13277,11 @@ static int kvm_sev_es_ins(struct kvm_vcpu *vcpu, unsigned int size,
 	for (;;) {
 		unsigned int count =
 			min_t(unsigned int, PAGE_SIZE / size, vcpu->arch.sev_pio_count);
-		if (!__emulator_pio_in(vcpu, size, port, count))
+		if (!__emulator_pio_in(vcpu, size, port, vcpu->arch.sev_pio_data, count))
 			break;
 
 		/* Emulation done by the kernel.  */
-		advance_sev_es_emulated_ins(vcpu);
+		advance_sev_es_emulated_ins(vcpu, count, size);
 		if (!vcpu->arch.sev_pio_count)
 			return 1;
 	}
-- 
2.31.1

[PATCH v2 6/8] KVM: x86: wean fast IN from emulator_pio_in

[Paolo Bonzini]

Use __emulator_pio_in() directly for fast PIO instead of bouncing through
emulator_pio_in() now that __emulator_pio_in() fills "val" when handling
in-kernel PIO.  vcpu->arch.pio.count is guaranteed to be '0', so this a
pure nop.

emulator_pio_in_emulated is now the last caller of emulator_pio_in.

No functional change intended.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/x86/kvm/x86.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 716ae5c92687..b824ffc63b17 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8886,7 +8886,7 @@ static int kvm_fast_pio_in(struct kvm_vcpu *vcpu, int size,
 	/* For size less than 4 we merge, else we zero extend */
 	val = (size < 4) ? kvm_rax_read(vcpu) : 0;
 
-	ret = emulator_pio_in(vcpu, size, port, &val, 1);
+	ret = __emulator_pio_in(vcpu, size, port, &val, 1);
 	if (ret) {
 		kvm_rax_write(vcpu, val);
 		return ret;
-- 
2.31.1

[PATCH v2 7/8] KVM: x86: de-underscorify __emulator_pio_in

[Paolo Bonzini]

Now all callers except emulator_pio_in_emulated are using
__emulator_pio_in/complete_emulator_pio_in explicitly.
Move the "either copy the result or attempt PIO" logic in
emulator_pio_in_emulated, and rename __emulator_pio_in to
just emulator_pio_in.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/x86/kvm/x86.c | 24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b824ffc63b17..1a017a5a680b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7626,8 +7626,8 @@ static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size,
 	return 0;
 }
 
-static int __emulator_pio_in(struct kvm_vcpu *vcpu, int size,
-			     unsigned short port, void *val, unsigned int count)
+static int emulator_pio_in(struct kvm_vcpu *vcpu, int size,
+      			   unsigned short port, void *val, unsigned int count)
 {
 	int r = emulator_pio_in_out(vcpu, size, port, val, count, true);
 	if (r)
@@ -7645,9 +7645,11 @@ static void complete_emulator_pio_in(struct kvm_vcpu *vcpu, void *val)
 	vcpu->arch.pio.count = 0;
 }
 
-static int emulator_pio_in(struct kvm_vcpu *vcpu, int size,
-			   unsigned short port, void *val, unsigned int count)
+static int emulator_pio_in_emulated(struct x86_emulate_ctxt *ctxt,
+				    int size, unsigned short port, void *val,
+				    unsigned int count)
 {
+	struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
 	if (vcpu->arch.pio.count) {
 		/*
 		 * Complete a previous iteration that required userspace I/O.
@@ -7660,15 +7662,7 @@ static int emulator_pio_in(struct kvm_vcpu *vcpu, int size,
 		return 1;
 	}
 
-	return __emulator_pio_in(vcpu, size, port, val, count);
-}
-
-static int emulator_pio_in_emulated(struct x86_emulate_ctxt *ctxt,
-				    int size, unsigned short port, void *val,
-				    unsigned int count)
-{
-	return emulator_pio_in(emul_to_vcpu(ctxt), size, port, val, count);
-
+	return emulator_pio_in(vcpu, size, port, val, count);
 }
 
 static int emulator_pio_out(struct kvm_vcpu *vcpu, int size,
@@ -8886,7 +8880,7 @@ static int kvm_fast_pio_in(struct kvm_vcpu *vcpu, int size,
 	/* For size less than 4 we merge, else we zero extend */
 	val = (size < 4) ? kvm_rax_read(vcpu) : 0;
 
-	ret = __emulator_pio_in(vcpu, size, port, &val, 1);
+	ret = emulator_pio_in(vcpu, size, port, &val, 1);
 	if (ret) {
 		kvm_rax_write(vcpu, val);
 		return ret;
@@ -13277,7 +13271,7 @@ static int kvm_sev_es_ins(struct kvm_vcpu *vcpu, unsigned int size,
 	for (;;) {
 		unsigned int count =
 			min_t(unsigned int, PAGE_SIZE / size, vcpu->arch.sev_pio_count);
-		if (!__emulator_pio_in(vcpu, size, port, vcpu->arch.sev_pio_data, count))
+		if (!emulator_pio_in(vcpu, size, port, vcpu->arch.sev_pio_data, count))
 			break;
 
 		/* Emulation done by the kernel.  */
-- 
2.31.1

[PATCH v2 8/8] KVM: SEV-ES: reuse advance_sev_es_emulated_ins for OUT too

[Paolo Bonzini]

complete_emulator_pio_in() only has to be called by
complete_sev_es_emulated_ins() now; therefore, all that the function does
now is adjust sev_pio_count and sev_pio_data.  Which is the same for
both IN and OUT.

No functional change intended.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/x86/kvm/x86.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1a017a5a680b..567d13405445 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -13206,6 +13206,12 @@ int kvm_sev_es_mmio_read(struct kvm_vcpu *vcpu, gpa_t gpa, unsigned int bytes,
 }
 EXPORT_SYMBOL_GPL(kvm_sev_es_mmio_read);
 
+static void advance_sev_es_emulated_pio(struct kvm_vcpu *vcpu, unsigned count, int size)
+{
+	vcpu->arch.sev_pio_count -= count;
+	vcpu->arch.sev_pio_data += count * size;
+}
+
 static int kvm_sev_es_outs(struct kvm_vcpu *vcpu, unsigned int size,
 			   unsigned int port);
 
@@ -13229,8 +13235,7 @@ static int kvm_sev_es_outs(struct kvm_vcpu *vcpu, unsigned int size,
 		int ret = emulator_pio_out(vcpu, size, port, vcpu->arch.sev_pio_data, count);
 
 		/* memcpy done already by emulator_pio_out.  */
-		vcpu->arch.sev_pio_count -= count;
-		vcpu->arch.sev_pio_data += count * size;
+		advance_sev_es_emulated_pio(vcpu, count, size);
 		if (!ret)
 			break;
 
@@ -13246,12 +13251,6 @@ static int kvm_sev_es_outs(struct kvm_vcpu *vcpu, unsigned int size,
 static int kvm_sev_es_ins(struct kvm_vcpu *vcpu, unsigned int size,
 			  unsigned int port);
 
-static void advance_sev_es_emulated_ins(struct kvm_vcpu *vcpu, unsigned count, int size)
-{
-	vcpu->arch.sev_pio_count -= count;
-	vcpu->arch.sev_pio_data += count * size;
-}
-
 static int complete_sev_es_emulated_ins(struct kvm_vcpu *vcpu)
 {
 	unsigned count = vcpu->arch.pio.count;
@@ -13259,7 +13258,7 @@ static int complete_sev_es_emulated_ins(struct kvm_vcpu *vcpu)
 	int port = vcpu->arch.pio.port;
 
 	complete_emulator_pio_in(vcpu, vcpu->arch.sev_pio_data);
-	advance_sev_es_emulated_ins(vcpu, count, size);
+	advance_sev_es_emulated_pio(vcpu, count, size);
 	if (vcpu->arch.sev_pio_count)
 		return kvm_sev_es_ins(vcpu, size, port);
 	return 1;
@@ -13275,7 +13274,7 @@ static int kvm_sev_es_ins(struct kvm_vcpu *vcpu, unsigned int size,
 			break;
 
 		/* Emulation done by the kernel.  */
-		advance_sev_es_emulated_ins(vcpu, count, size);
+		advance_sev_es_emulated_pio(vcpu, count, size);
 		if (!vcpu->arch.sev_pio_count)
 			return 1;
 	}
-- 
2.31.1