[PATCH 0/2] KVM: Introduce ioeventfd read support

[PATCH 0/2] KVM: Introduce ioeventfd read support

[Amey Narkhede]

The first patch updates linux headers to
add ioeventfd read support while the
second patch can be used to test the
ioeventfd read feature with kvm-unit-test
which reads from specified guest addres.
Make sure the address provided in
kvm_set_ioeventfd_read matches with address
in x86/ioeventfd_read test in kvm-unit-tests.

Amey Narkhede (2):
  linux-headers: Add support for reads in ioeventfd
  kvm: Add ioeventfd read test code

 accel/kvm/kvm-all.c       | 55 +++++++++++++++++++++++++++++++++++++++
 linux-headers/linux/kvm.h |  5 +++-
 2 files changed, 59 insertions(+), 1 deletion(-)

-- 
2.28.0

[PATCH 1/2] linux-headers: Add support for reads in ioeventfd

[Amey Narkhede]

This patch introduces a new flag KVM_IOEVENTFD_FLAG_DATAREAD
in ioeventfd to enable receiving a notification when a
guest reads from registered PIO/MMIO address.

Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
---
 linux-headers/linux/kvm.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
index 43580c767c..3e71d15a53 100644
--- a/linux-headers/linux/kvm.h
+++ b/linux-headers/linux/kvm.h
@@ -695,6 +695,7 @@ struct kvm_guest_debug {
 
 enum {
 	kvm_ioeventfd_flag_nr_datamatch,
+	kvm_ioeventfd_flag_nr_dataread,
 	kvm_ioeventfd_flag_nr_pio,
 	kvm_ioeventfd_flag_nr_deassign,
 	kvm_ioeventfd_flag_nr_virtio_ccw_notify,
@@ -703,6 +704,7 @@ enum {
 };
 
 #define KVM_IOEVENTFD_FLAG_DATAMATCH (1 << kvm_ioeventfd_flag_nr_datamatch)
+#define KVM_IOEVENTFD_FLAG_DATAREAD (1 << kvm_ioeventfd_flag_nr_dataread)
 #define KVM_IOEVENTFD_FLAG_PIO       (1 << kvm_ioeventfd_flag_nr_pio)
 #define KVM_IOEVENTFD_FLAG_DEASSIGN  (1 << kvm_ioeventfd_flag_nr_deassign)
 #define KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY \
@@ -712,11 +714,12 @@ enum {
 
 struct kvm_ioeventfd {
 	__u64 datamatch;
+	__u64 dataread;
 	__u64 addr;        /* legal pio/mmio address */
 	__u32 len;         /* 1, 2, 4, or 8 bytes; or 0 to ignore length */
 	__s32 fd;
 	__u32 flags;
-	__u8  pad[36];
+	__u8  pad[28];
 };
 
 #define KVM_X86_DISABLE_EXITS_MWAIT          (1 << 0)
-- 
2.28.0

[PATCH 2/2] kvm: Add ioeventfd read test code

[Amey Narkhede]

This patch adds kvm_set_ioeventfd_read and
dummy_notifier_read functons to test ioeventfd
read support. When the guess writes to address
provided in kvm_set_ioeventfd_read function,
dummy_notifier_read prints to stdio.

Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
---
 accel/kvm/kvm-all.c | 55 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 9ef5daf4c5..357e74d84c 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -1006,6 +1006,43 @@ static uint32_t adjust_ioeventfd_endianness(uint32_t val, uint32_t size)
     return val;
 }
 
+static void dummy_notifier_read(EventNotifier *n)
+{
+    printf("Received ioeventfd read event\n");
+    event_notifier_test_and_clear(n);
+}
+
+static int kvm_set_ioeventfd_read(int fd, hwaddr addr, uint64_t val,
+				  uint64_t size, bool datamatch)
+{
+	int ret;
+	struct kvm_ioeventfd ioevent = {
+        	.datamatch = datamatch ? adjust_ioeventfd_endianness(val, size) : 0,
+		.dataread = val,
+		.addr = addr,
+		.len = size,
+		.flags = KVM_IOEVENTFD_FLAG_DATAREAD,
+		.fd = fd,
+	};
+
+	if (!kvm_enabled()) {
+		return -ENOSYS;
+	}
+
+	if (datamatch) {
+            ioevent.flags |= KVM_IOEVENTFD_FLAG_DATAMATCH;
+	}
+
+	ret = kvm_vm_ioctl(kvm_state, KVM_IOEVENTFD, &ioevent);
+
+	if (ret < 0) {
+		return -errno;
+	}
+
+	return 0;
+}
+
+
 static int kvm_set_ioeventfd_mmio(int fd, hwaddr addr, uint32_t val,
                                   bool assign, uint32_t size, bool datamatch)
 {
@@ -2012,6 +2049,7 @@ static int kvm_init(MachineState *ms)
     KVMState *s;
     const KVMCapabilityInfo *missing_cap;
     int ret;
+    int efd = -1;
     int type = 0;
     const char *kvm_type;
     uint64_t dirty_log_manual_caps;
@@ -2253,6 +2291,22 @@ static int kvm_init(MachineState *ms)
     }
 
     cpus_register_accel(&kvm_cpus);
+
+    EventNotifier *e = g_malloc0(sizeof(EventNotifier));
+    ret = event_notifier_init(e, false);
+    if (ret < 0) {
+	printf("Failed to initialize EventNotifier\n");
+    }
+    else {
+        AioContext *ctx = qemu_get_aio_context();
+        efd = event_notifier_get_fd(e);
+        aio_set_event_notifier(ctx, e, false, dummy_notifier_read, NULL);
+        ret = kvm_set_ioeventfd_read(efd, 0xff01003f, 123, 8, false);
+        if (ret < 0)
+            printf("ioeventfd read failed\n");
+    }
+
+
     return 0;
 
 err:
@@ -2268,6 +2322,7 @@ err:
     return ret;
 }
 
+
 void kvm_set_sigmask_len(KVMState *s, unsigned int sigmask_len)
 {
     s->sigmask_len = sigmask_len;
-- 
2.28.0

Re: [PATCH 0/2] KVM: Introduce ioeventfd read support

[no-reply]

Patchew URL: https://patchew.org/QEMU/20201020170056.433528-1-ameynarkhede03@gmail.com/



Hi,

This series seems to have some coding style problems. See output below for
more information:

Type: series
Message-id: 20201020170056.433528-1-ameynarkhede03@gmail.com
Subject: [PATCH 0/2] KVM: Introduce ioeventfd read support

=== TEST SCRIPT BEGIN ===
#!/bin/bash
git rev-parse base > /dev/null || exit 0
git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram
./scripts/checkpatch.pl --mailback base..
=== TEST SCRIPT END ===

Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
From https://github.com/patchew-project/qemu
 - [tag update]      patchew/20201020163738.27700-1-alex.bennee@linaro.org -> patchew/20201020163738.27700-1-alex.bennee@linaro.org
 * [new tag]         patchew/20201020170056.433528-1-ameynarkhede03@gmail.com -> patchew/20201020170056.433528-1-ameynarkhede03@gmail.com
Switched to a new branch 'test'
eccca33 kvm: Add ioeventfd read test code
33b3de6 linux-headers: Add support for reads in ioeventfd

=== OUTPUT BEGIN ===
1/2 Checking commit 33b3de672219 (linux-headers: Add support for reads in ioeventfd)
2/2 Checking commit eccca33098c6 (kvm: Add ioeventfd read test code)
ERROR: code indent should never use tabs
#31: FILE: accel/kvm/kvm-all.c:1016:
+^I^I^I^I  uint64_t size, bool datamatch)$

ERROR: code indent should never use tabs
#33: FILE: accel/kvm/kvm-all.c:1018:
+^Iint ret;$

ERROR: code indent should never use tabs
#34: FILE: accel/kvm/kvm-all.c:1019:
+^Istruct kvm_ioeventfd ioevent = {$

WARNING: line over 80 characters
#35: FILE: accel/kvm/kvm-all.c:1020:
+               .datamatch = datamatch ? adjust_ioeventfd_endianness(val, size) : 0,

ERROR: code indent should never use tabs
#35: FILE: accel/kvm/kvm-all.c:1020:
+        ^I.datamatch = datamatch ? adjust_ioeventfd_endianness(val, size) : 0,$

ERROR: code indent should never use tabs
#36: FILE: accel/kvm/kvm-all.c:1021:
+^I^I.dataread = val,$

ERROR: code indent should never use tabs
#37: FILE: accel/kvm/kvm-all.c:1022:
+^I^I.addr = addr,$

ERROR: code indent should never use tabs
#38: FILE: accel/kvm/kvm-all.c:1023:
+^I^I.len = size,$

ERROR: code indent should never use tabs
#39: FILE: accel/kvm/kvm-all.c:1024:
+^I^I.flags = KVM_IOEVENTFD_FLAG_DATAREAD,$

ERROR: code indent should never use tabs
#40: FILE: accel/kvm/kvm-all.c:1025:
+^I^I.fd = fd,$

ERROR: code indent should never use tabs
#41: FILE: accel/kvm/kvm-all.c:1026:
+^I};$

ERROR: code indent should never use tabs
#43: FILE: accel/kvm/kvm-all.c:1028:
+^Iif (!kvm_enabled()) {$

ERROR: code indent should never use tabs
#44: FILE: accel/kvm/kvm-all.c:1029:
+^I^Ireturn -ENOSYS;$

ERROR: code indent should never use tabs
#45: FILE: accel/kvm/kvm-all.c:1030:
+^I}$

ERROR: code indent should never use tabs
#47: FILE: accel/kvm/kvm-all.c:1032:
+^Iif (datamatch) {$

ERROR: code indent should never use tabs
#49: FILE: accel/kvm/kvm-all.c:1034:
+^I}$

ERROR: code indent should never use tabs
#51: FILE: accel/kvm/kvm-all.c:1036:
+^Iret = kvm_vm_ioctl(kvm_state, KVM_IOEVENTFD, &ioevent);$

ERROR: code indent should never use tabs
#53: FILE: accel/kvm/kvm-all.c:1038:
+^Iif (ret < 0) {$

ERROR: code indent should never use tabs
#54: FILE: accel/kvm/kvm-all.c:1039:
+^I^Ireturn -errno;$

ERROR: code indent should never use tabs
#55: FILE: accel/kvm/kvm-all.c:1040:
+^I}$

ERROR: code indent should never use tabs
#57: FILE: accel/kvm/kvm-all.c:1042:
+^Ireturn 0;$

ERROR: code indent should never use tabs
#80: FILE: accel/kvm/kvm-all.c:2298:
+^Iprintf("Failed to initialize EventNotifier\n");$

ERROR: else should follow close brace '}'
#82: FILE: accel/kvm/kvm-all.c:2300:
+    }
+    else {

ERROR: braces {} are necessary for all arms of this statement
#87: FILE: accel/kvm/kvm-all.c:2305:
+        if (ret < 0)
[...]

total: 23 errors, 1 warnings, 79 lines checked

Patch 2/2 has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.

=== OUTPUT END ===

Test command exited with code: 1


The full log is available at
http://patchew.org/logs/20201020170056.433528-1-ameynarkhede03@gmail.com/testing.checkpatch/?type=message.
---
Email generated automatically by Patchew [https://patchew.org/].
Please send your feedback to patchew-devel@redhat.com

Re: [PATCH 0/2] KVM: Introduce ioeventfd read support

[Amey Narkhede]

[-- Attachment #1: Type: text/plain, Size: 886 bytes --]

On 20/10/20 10:30PM, Amey Narkhede wrote:

Please ignore this mail. I meant to send
this mail to stefan but due to me being careless
I forgot that I previously configured git-publish
for qemu and didn't check the final
message before hitting send.
> The first patch updates linux headers to
> add ioeventfd read support while the
> second patch can be used to test the
> ioeventfd read feature with kvm-unit-test
> which reads from specified guest addres.
> Make sure the address provided in
> kvm_set_ioeventfd_read matches with address
> in x86/ioeventfd_read test in kvm-unit-tests.
>
> Amey Narkhede (2):
>   linux-headers: Add support for reads in ioeventfd
>   kvm: Add ioeventfd read test code
>
>  accel/kvm/kvm-all.c       | 55 +++++++++++++++++++++++++++++++++++++++
>  linux-headers/linux/kvm.h |  5 +++-
>  2 files changed, 59 insertions(+), 1 deletion(-)
>
> --
> 2.28.0
>

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

Re: [PATCH 0/2] KVM: Introduce ioeventfd read support

[Paolo Bonzini]

On 20/10/20 19:00, Amey Narkhede wrote:
> The first patch updates linux headers to
> add ioeventfd read support while the
> second patch can be used to test the
> ioeventfd read feature with kvm-unit-test
> which reads from specified guest addres.
> Make sure the address provided in
> kvm_set_ioeventfd_read matches with address
> in x86/ioeventfd_read test in kvm-unit-tests.
> 
> Amey Narkhede (2):
>   linux-headers: Add support for reads in ioeventfd
>   kvm: Add ioeventfd read test code
> 
>  accel/kvm/kvm-all.c       | 55 +++++++++++++++++++++++++++++++++++++++
>  linux-headers/linux/kvm.h |  5 +++-
>  2 files changed, 59 insertions(+), 1 deletion(-)
> 

Hi,

in what occasions is this useful?

Paolo