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- Apply 0001-kvm-reuse-per-vcpu-stats-fd-to-avoid-vcpu-interruption.patch and 0002-vdpa-stop-all-svq-on-device-deletion.patch

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eabdullin 2023-08-03 12:23:35 +03:00
parent ffc1c33ba7
commit 6ffea859dd
3 changed files with 223 additions and 1 deletions
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143
SOURCES/0001-kvm-reuse-per-vcpu-stats-fd-to-avoid-vcpu-interruption.patch Normal file
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@ -0,0 +1,143 @@
From 3b6f485275ae95a81eec589d2773b86ca9ddec4d Mon Sep 17 00:00:00 2001
From: Marcelo Tosatti <mtosatti@redhat.com>
Date: Sun, 18 Jun 2023 23:24:40 +0200
Subject: [PATCH] kvm: reuse per-vcpu stats fd to avoid vcpu interruption
A regression has been detected in latency testing of KVM guests.
More specifically, it was observed that the cyclictest
numbers inside of an isolated vcpu (running on isolated pcpu) are:
Where a maximum of 50us is acceptable.
The implementation of KVM_GET_STATS_FD uses run_on_cpu to query
per vcpu statistics, which interrupts the vcpu (and is unnecessary).
To fix this, open the per vcpu stats fd on vcpu initialization,
and read from that fd from QEMU's main thread.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
accel/kvm/kvm-all.c | 30 +++++++++++++++---------------
include/hw/core/cpu.h | 1 +
2 files changed, 16 insertions(+), 15 deletions(-)
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 7679f397aec0..9aa898db142e 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -450,6 +450,8 @@ int kvm_init_vcpu(CPUState *cpu, Error **errp)
"kvm_init_vcpu: kvm_arch_init_vcpu failed (%lu)",
kvm_arch_vcpu_id(cpu));
}
+ cpu->kvm_vcpu_stats_fd = kvm_vcpu_ioctl(cpu, KVM_GET_STATS_FD, NULL);
+
err:
return ret;
}
@@ -4007,7 +4009,7 @@ static StatsDescriptors *find_stats_descriptors(StatsTarget target, int stats_fd
/* Read stats header */
kvm_stats_header = &descriptors->kvm_stats_header;
- ret = read(stats_fd, kvm_stats_header, sizeof(*kvm_stats_header));
+ ret = pread(stats_fd, kvm_stats_header, sizeof(*kvm_stats_header), 0);
if (ret != sizeof(*kvm_stats_header)) {
error_setg(errp, "KVM stats: failed to read stats header: "
"expected %zu actual %zu",
@@ -4038,7 +4040,8 @@ static StatsDescriptors *find_stats_descriptors(StatsTarget target, int stats_fd
}
static void query_stats(StatsResultList **result, StatsTarget target,
- strList *names, int stats_fd, Error **errp)
+ strList *names, int stats_fd, CPUState *cpu,
+ Error **errp)
{
struct kvm_stats_desc *kvm_stats_desc;
struct kvm_stats_header *kvm_stats_header;
@@ -4096,7 +4099,7 @@ static void query_stats(StatsResultList **result, StatsTarget target,
break;
case STATS_TARGET_VCPU:
add_stats_entry(result, STATS_PROVIDER_KVM,
- current_cpu->parent_obj.canonical_path,
+ cpu->parent_obj.canonical_path,
stats_list);
break;
default:
@@ -4133,10 +4136,9 @@ static void query_stats_schema(StatsSchemaList **result, StatsTarget target,
add_stats_schema(result, STATS_PROVIDER_KVM, target, stats_list);
}
-static void query_stats_vcpu(CPUState *cpu, run_on_cpu_data data)
+static void query_stats_vcpu(CPUState *cpu, StatsArgs *kvm_stats_args)
{
- StatsArgs *kvm_stats_args = (StatsArgs *) data.host_ptr;
- int stats_fd = kvm_vcpu_ioctl(cpu, KVM_GET_STATS_FD, NULL);
+ int stats_fd = cpu->kvm_vcpu_stats_fd;
Error *local_err = NULL;
if (stats_fd == -1) {
@@ -4145,14 +4147,13 @@ static void query_stats_vcpu(CPUState *cpu, run_on_cpu_data data)
return;
}
query_stats(kvm_stats_args->result.stats, STATS_TARGET_VCPU,
- kvm_stats_args->names, stats_fd, kvm_stats_args->errp);
- close(stats_fd);
+ kvm_stats_args->names, stats_fd, cpu,
+ kvm_stats_args->errp);
}
-static void query_stats_schema_vcpu(CPUState *cpu, run_on_cpu_data data)
+static void query_stats_schema_vcpu(CPUState *cpu, StatsArgs *kvm_stats_args)
{
- StatsArgs *kvm_stats_args = (StatsArgs *) data.host_ptr;
- int stats_fd = kvm_vcpu_ioctl(cpu, KVM_GET_STATS_FD, NULL);
+ int stats_fd = cpu->kvm_vcpu_stats_fd;
Error *local_err = NULL;
if (stats_fd == -1) {
@@ -4162,7 +4163,6 @@ static void query_stats_schema_vcpu(CPUState *cpu, run_on_cpu_data data)
}
query_stats_schema(kvm_stats_args->result.schema, STATS_TARGET_VCPU, stats_fd,
kvm_stats_args->errp);
- close(stats_fd);
}
static void query_stats_cb(StatsResultList **result, StatsTarget target,
@@ -4180,7 +4180,7 @@ static void query_stats_cb(StatsResultList **result, StatsTarget target,
error_setg_errno(errp, errno, "KVM stats: ioctl failed");
return;
}
- query_stats(result, target, names, stats_fd, errp);
+ query_stats(result, target, names, stats_fd, NULL, errp);
close(stats_fd);
break;
}
@@ -4194,7 +4194,7 @@ static void query_stats_cb(StatsResultList **result, StatsTarget target,
if (!apply_str_list_filter(cpu->parent_obj.canonical_path, targets)) {
continue;
}
- run_on_cpu(cpu, query_stats_vcpu, RUN_ON_CPU_HOST_PTR(&stats_args));
+ query_stats_vcpu(cpu, &stats_args);
}
break;
}
@@ -4220,6 +4220,6 @@ void query_stats_schemas_cb(StatsSchemaList **result, Error **errp)
if (first_cpu) {
stats_args.result.schema = result;
stats_args.errp = errp;
- run_on_cpu(first_cpu, query_stats_schema_vcpu, RUN_ON_CPU_HOST_PTR(&stats_args));
+ query_stats_schema_vcpu(first_cpu, &stats_args);
}
}
diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index 4871ad85f074..3b765beb9b1c 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -402,6 +402,7 @@ struct CPUState {
struct kvm_dirty_gfn *kvm_dirty_gfns;
uint32_t kvm_fetch_index;
uint64_t dirty_pages;
+ int kvm_vcpu_stats_fd;
/* Use by accel-block: CPU is executing an ioctl() */
QemuLockCnt in_ioctl_lock;

69
SOURCES/0002-vdpa-stop-all-svq-on-device-deletion.patch Normal file
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@ -0,0 +1,69 @@
From 2e1a9de96b487cf818a22d681cad8d3f5d18dcca Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= <eperezma@redhat.com>
Date: Thu, 9 Feb 2023 18:00:04 +0100
Subject: [PATCH] vdpa: stop all svq on device deletion
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Not stopping them leave the device in a bad state when virtio-net
fronted device is unplugged with device_del monitor command.
This is not triggable in regular poweroff or qemu forces shutdown
because cleanup is called right after vhost_vdpa_dev_start(false). But
devices hot unplug does not call vdpa device cleanups. This lead to all
the vhost_vdpa devices without stop the SVQ but the last.
Fix it and clean the code, making it symmetric with
vhost_vdpa_svqs_start.
Fixes: dff4426fa656 ("vhost: Add Shadow VirtQueue kick forwarding capabilities")
Reported-by: Lei Yang <leiyang@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <20230209170004.899472-1-eperezma@redhat.com>
Tested-by: Laurent Vivier <lvivier@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
hw/virtio/vhost-vdpa.c | 17 ++---------------
1 file changed, 2 insertions(+), 15 deletions(-)
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 542e003101b5..df3a1e92acb0 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -689,26 +689,11 @@ static int vhost_vdpa_get_device_id(struct vhost_dev *dev,
return ret;
}
-static void vhost_vdpa_reset_svq(struct vhost_vdpa *v)
-{
- if (!v->shadow_vqs_enabled) {
- return;
- }
-
- for (unsigned i = 0; i < v->shadow_vqs->len; ++i) {
- VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, i);
- vhost_svq_stop(svq);
- }
-}
-
static int vhost_vdpa_reset_device(struct vhost_dev *dev)
{
- struct vhost_vdpa *v = dev->opaque;
int ret;
uint8_t status = 0;
- vhost_vdpa_reset_svq(v);
-
ret = vhost_vdpa_call(dev, VHOST_VDPA_SET_STATUS, &status);
trace_vhost_vdpa_reset_device(dev, status);
return ret;
@@ -1100,6 +1085,8 @@ static void vhost_vdpa_svqs_stop(struct vhost_dev *dev)
for (unsigned i = 0; i < v->shadow_vqs->len; ++i) {
VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, i);
+
+ vhost_svq_stop(svq);
vhost_vdpa_svq_unmap_rings(dev, svq);
event_notifier_cleanup(&svq->hdev_kick);

12
SPECS/qemu-kvm.spec
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@ -148,7 +148,7 @@ Obsoletes: %{name}-block-ssh <= %{epoch}:%{version} \
Summary: QEMU is a machine emulator and virtualizer
Name: qemu-kvm
Version: 7.2.0
Release: 14%{?rcrel}%{?dist}%{?cc_suffix}.1
Release: 14%{?rcrel}%{?dist}%{?cc_suffix}.3.alma
# Epoch because we pushed a qemu-1.0 package. AIUI this can't ever be dropped
# Epoch 15 used for RHEL 8
# Epoch 17 used for RHEL 9 (due to release versioning offset in RHEL 8.5)
@ -419,6 +419,12 @@ Patch135: kvm-intel-iommu-fail-DEVIOTLB_UNMAP-without-dt-mode.patch
# For bz#2203745 - Disk detach is unsuccessful while the guest is still booting [rhel-9.2.0.z]
Patch136: kvm-acpi-pcihp-allow-repeating-hot-unplug-requests.patch
# Patches were taken from upstream:
# https://github.com/qemu/qemu/commit/3b6f485275ae95a81eec589d2773b86ca9ddec4d
Patch1001: 0001-kvm-reuse-per-vcpu-stats-fd-to-avoid-vcpu-interruption.patch
# https://github.com/qemu/qemu/commit/2e1a9de96b487cf818a22d681cad8d3f5d18dcca
Patch1002: 0002-vdpa-stop-all-svq-on-device-deletion.patch
%if %{have_clang}
BuildRequires: clang
%if %{have_safe_stack}
@ -1448,6 +1454,10 @@ useradd -r -u 107 -g qemu -G kvm -d / -s /sbin/nologin \
%endif
%changelog
* Thu Aug 03 2023 Eduard Abdullin <eabdullin@almalinux.org> - 7.2.0-14.el9_2.3.alma
- Apply 0001-kvm-reuse-per-vcpu-stats-fd-to-avoid-vcpu-interruption.patch
and 0002-vdpa-stop-all-svq-on-device-deletion.patch
* Thu May 25 2023 Miroslav Rezanina <mrezanin@redhat.com> - 7.2.0-14.el9_2.1
- kvm-acpi-pcihp-allow-repeating-hot-unplug-requests.patch [bz#2203745]
- Resolves: bz#2203745