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* Tue Jan 27 2026 Jon Maloy <jmaloy@redhat.com> - 10.1.0-12

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- kvm-block-Improve-comments-in-BlockLimits.patch [RHEL-132989]
- kvm-block-Expose-block-limits-for-images-in-QMP.patch [RHEL-132989]
- kvm-qemu-img-info-Optionally-show-block-limits.patch [RHEL-132989]
- kvm-qemu-img-info-Add-cache-mode-option.patch [RHEL-132989]
- kvm-hw-intc-ioapic-Fix-ACCEL_KERNEL_GSI_IRQFD_POSSIBLE-t.patch [RHEL-140187]
- kvm-q35-increase-default-tseg-size.patch [RHEL-139057]
- Resolves: RHEL-132989
  (Expose block limits of block nodes in QMP and qemu-img [rhel-9])
- Resolves: RHEL-140187
  (Intel IOMMU VM freezes: "call_irq_handler: 3.37 No irq handler for vector"[rhel-9.8])
- Resolves: RHEL-139057
  ([qemu, rhel-9] increase default TSEG size)
This commit is contained in:
Jon Maloy 2026-01-27 10:25:57 -05:00
parent c60e175901
commit 7d7aec1bd3
7 changed files with 903 additions and 1 deletions
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255
kvm-block-Expose-block-limits-for-images-in-QMP.patch Normal file
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@ -0,0 +1,255 @@
From 8524b4a772f47d2be59ce2f07c7c6d5a8af056d0 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Fri, 24 Oct 2025 14:30:38 +0200
Subject: [PATCH 2/6] block: Expose block limits for images in QMP
RH-Author: Kevin Wolf <kwolf@redhat.com>
RH-MergeRequest: 440: block: Expose block limits in monitor and qemu-img info
RH-Jira: RHEL-132989
RH-Acked-by: Hanna Czenczek <hreitz@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Commit: [2/4] 2c68f297c55a64249fd10ab2e06ae9446096a0a9 (kmwolf/centos-qemu-kvm)
This information can be useful both for debugging and for management
tools trying to configure guest devices with the optimal limits
(possibly across multiple hosts). There is no reason not to make it
available, so just add it to BlockNodeInfo.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-ID: <20251024123041.51254-3-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit d2634e18286a5772f04cc724e64f8b16a2124587)
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
block/qapi.c | 34 ++++++++++++++--
qapi/block-core.json | 66 ++++++++++++++++++++++++++++++++
tests/qemu-iotests/184 | 5 ++-
tests/qemu-iotests/184.out | 8 ----
tests/qemu-iotests/common.filter | 3 +-
5 files changed, 102 insertions(+), 14 deletions(-)
diff --git a/block/qapi.c b/block/qapi.c
index 12fbf8d1b7..54521d0a68 100644
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -235,7 +235,8 @@ int bdrv_query_snapshot_info_list(BlockDriverState *bs,
* in @info, setting @errp on error.
*/
static void GRAPH_RDLOCK
-bdrv_do_query_node_info(BlockDriverState *bs, BlockNodeInfo *info, Error **errp)
+bdrv_do_query_node_info(BlockDriverState *bs, BlockNodeInfo *info, bool limits,
+ Error **errp)
{
int64_t size;
const char *backing_filename;
@@ -269,6 +270,33 @@ bdrv_do_query_node_info(BlockDriverState *bs, BlockNodeInfo *info, Error **errp)
info->dirty_flag = bdi.is_dirty;
info->has_dirty_flag = true;
}
+
+ if (limits) {
+ info->limits = g_new(BlockLimitsInfo, 1);
+ *info->limits = (BlockLimitsInfo) {
+ .request_alignment = bs->bl.request_alignment,
+ .has_max_discard = bs->bl.max_pdiscard != 0,
+ .max_discard = bs->bl.max_pdiscard,
+ .has_discard_alignment = bs->bl.pdiscard_alignment != 0,
+ .discard_alignment = bs->bl.pdiscard_alignment,
+ .has_max_write_zeroes = bs->bl.max_pwrite_zeroes != 0,
+ .max_write_zeroes = bs->bl.max_pwrite_zeroes,
+ .has_write_zeroes_alignment = bs->bl.pwrite_zeroes_alignment != 0,
+ .write_zeroes_alignment = bs->bl.pwrite_zeroes_alignment,
+ .has_opt_transfer = bs->bl.opt_transfer != 0,
+ .opt_transfer = bs->bl.opt_transfer,
+ .has_max_transfer = bs->bl.max_transfer != 0,
+ .max_transfer = bs->bl.max_transfer,
+ .has_max_hw_transfer = bs->bl.max_hw_transfer != 0,
+ .max_hw_transfer = bs->bl.max_hw_transfer,
+ .max_iov = bs->bl.max_iov,
+ .has_max_hw_iov = bs->bl.max_hw_iov != 0,
+ .max_hw_iov = bs->bl.max_hw_iov,
+ .min_mem_alignment = bs->bl.min_mem_alignment,
+ .opt_mem_alignment = bs->bl.opt_mem_alignment,
+ };
+ }
+
info->format_specific = bdrv_get_specific_info(bs, &err);
if (err) {
error_propagate(errp, err);
@@ -343,7 +371,7 @@ void bdrv_query_image_info(BlockDriverState *bs,
ImageInfo *info;
info = g_new0(ImageInfo, 1);
- bdrv_do_query_node_info(bs, qapi_ImageInfo_base(info), errp);
+ bdrv_do_query_node_info(bs, qapi_ImageInfo_base(info), true, errp);
if (*errp) {
goto fail;
}
@@ -397,7 +425,7 @@ void bdrv_query_block_graph_info(BlockDriverState *bs,
BdrvChild *c;
info = g_new0(BlockGraphInfo, 1);
- bdrv_do_query_node_info(bs, qapi_BlockGraphInfo_base(info), errp);
+ bdrv_do_query_node_info(bs, qapi_BlockGraphInfo_base(info), false, errp);
if (*errp) {
goto fail;
}
diff --git a/qapi/block-core.json b/qapi/block-core.json
index dc6eb4ae23..2c037183f0 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -275,6 +275,69 @@
'file': 'ImageInfoSpecificFileWrapper'
} }
+##
+# @BlockLimitsInfo:
+#
+# @request-alignment: Alignment requirement, in bytes, for
+# offset/length of I/O requests.
+#
+# @max-discard: Maximum number of bytes that can be discarded at once.
+# If not present, there is no specific maximum.
+#
+# @discard-alignment: Optimal alignment for discard requests in bytes.
+# Note that this doesn't have to be a power of two. If not
+# present, discards don't have a alignment requirement different
+# from @request-alignment.
+#
+# @max-write-zeroes: Maximum number of bytes that can be zeroed out at
+# once. If not present, there is no specific maximum.
+#
+# @write-zeroes-alignment: Optimal alignment for write zeroes requests
+# in bytes. Note that this doesn't have to be a power of two. If
+# not present, write_zeroes doesn't have a alignment requirement
+# different from @request-alignment.
+#
+# @opt-transfer: Optimal transfer length in bytes. If not present,
+# there is no preferred size.
+#
+# @max-transfer: Maximal transfer length in bytes. If not present,
+# there is no specific maximum.
+#
+# @max-hw-transfer: Maximal hardware transfer length in bytes.
+# Applies whenever transfers to the device bypass the kernel I/O
+# scheduler, for example with SG_IO. If not present, there is no
+# specific maximum.
+#
+# @max-iov: Maximum number of scatter/gather elements
+#
+# @max-hw-iov: Maximum number of scatter/gather elements allowed by
+# the hardware. Applies whenever transfers to the device bypass
+# the kernel I/O scheduler, for example with SG_IO. If not
+# present, the hardware limits is unknown and @max-iov is always
+# used.
+#
+# @min-mem-alignment: Minimal required memory alignment in bytes for
+# zero-copy I/O to succeed. For unaligned requests, a bounce
+# buffer will be used.
+#
+# @opt-mem-alignment: Optimal memory alignment in bytes. This is the
+# alignment used for any buffer allocations QEMU performs
+# internally.
+##
+{ 'struct': 'BlockLimitsInfo',
+ 'data': { 'request-alignment': 'uint32',
+ '*max-discard': 'uint64',
+ '*discard-alignment': 'uint32',
+ '*max-write-zeroes': 'uint64',
+ '*write-zeroes-alignment': 'uint32',
+ '*opt-transfer': 'uint32',
+ '*max-transfer': 'uint32',
+ '*max-hw-transfer': 'uint32',
+ 'max-iov': 'int',
+ '*max-hw-iov': 'int',
+ 'min-mem-alignment': 'size',
+ 'opt-mem-alignment': 'size' } }
+
##
# @BlockNodeInfo:
#
@@ -304,6 +367,8 @@
#
# @snapshots: list of VM snapshots
#
+# @limits: block limits that are used for I/O on the node (Since 10.2)
+#
# @format-specific: structure supplying additional format-specific
# information (since 1.7)
#
@@ -315,6 +380,7 @@
'*cluster-size': 'int', '*encrypted': 'bool', '*compressed': 'bool',
'*backing-filename': 'str', '*full-backing-filename': 'str',
'*backing-filename-format': 'str', '*snapshots': ['SnapshotInfo'],
+ '*limits': 'BlockLimitsInfo',
'*format-specific': 'ImageInfoSpecific' } }
##
diff --git a/tests/qemu-iotests/184 b/tests/qemu-iotests/184
index e4cbcd8634..6d0afe9d38 100755
--- a/tests/qemu-iotests/184
+++ b/tests/qemu-iotests/184
@@ -45,8 +45,9 @@ do_run_qemu()
run_qemu()
{
- do_run_qemu "$@" 2>&1 | _filter_testdir | _filter_qemu | _filter_qmp\
- | _filter_qemu_io | _filter_generated_node_ids
+ do_run_qemu "$@" 2>&1 | _filter_testdir | _filter_qemu | _filter_qmp \
+ | _filter_qemu_io | _filter_generated_node_ids \
+ | _filter_img_info
}
test_throttle=$($QEMU_IMG --help|grep throttle)
diff --git a/tests/qemu-iotests/184.out b/tests/qemu-iotests/184.out
index ef99bb2e9a..52692b6b3b 100644
--- a/tests/qemu-iotests/184.out
+++ b/tests/qemu-iotests/184.out
@@ -41,12 +41,6 @@ Testing:
},
"iops_wr": 0,
"ro": false,
- "children": [
- {
- "node-name": "disk0",
- "child": "file"
- }
- ],
"node-name": "throttle0",
"backing_file_depth": 1,
"drv": "throttle",
@@ -75,8 +69,6 @@ Testing:
},
"iops_wr": 0,
"ro": false,
- "children": [
- ],
"node-name": "disk0",
"backing_file_depth": 0,
"drv": "null-co",
diff --git a/tests/qemu-iotests/common.filter b/tests/qemu-iotests/common.filter
index 35c0fc0d20..cd8b506dba 100644
--- a/tests/qemu-iotests/common.filter
+++ b/tests/qemu-iotests/common.filter
@@ -230,6 +230,7 @@ _filter_img_info()
discard=0
regex_json_spec_start='^ *"format-specific": \{'
regex_json_child_start='^ *"children": \['
+ regex_json_limit_start='^ *"limits": \{'
gsed -e "s#$REMOTE_TEST_DIR#TEST_DIR#g" \
-e "s#$IMGPROTO:$TEST_DIR#TEST_DIR#g" \
-e "s#$TEST_DIR#TEST_DIR#g" \
@@ -262,7 +263,7 @@ _filter_img_info()
discard=1
elif [[ $line =~ "Child node '/" ]]; then
discard=1
- elif [[ $line =~ $regex_json_spec_start ]]; then
+ elif [[ $line =~ $regex_json_spec_start || $line =~ $regex_json_limit_start ]]; then
discard=2
regex_json_end="^${line%%[^ ]*}\\},? *$"
elif [[ $line =~ $regex_json_child_start ]]; then
--
2.52.0

98
kvm-block-Improve-comments-in-BlockLimits.patch Normal file
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@ -0,0 +1,98 @@
From 43ef7d6a38dd596315f1b66c5736df5d732abc95 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Fri, 24 Oct 2025 14:30:37 +0200
Subject: [PATCH 1/6] block: Improve comments in BlockLimits
RH-Author: Kevin Wolf <kwolf@redhat.com>
RH-MergeRequest: 440: block: Expose block limits in monitor and qemu-img info
RH-Jira: RHEL-132989
RH-Acked-by: Hanna Czenczek <hreitz@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Commit: [1/4] 89b5ee003a4c87cd7736b9ca674baffdd92e38e5 (kmwolf/centos-qemu-kvm)
Patches to expose the limits in QAPI have made clear that the existing
documentation of BlockLimits could be improved: The meaning of
min_mem_alignment and opt_mem_alignment could be clearer, and talking
about better alignment values isn't helpful when we only detect these
values and never choose them.
Make the changes in the BlockLimits documentation now, so that the
patches exposing the fields in QAPI can use descriptions consistent with
it.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20251024123041.51254-2-kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 46dd683d56b1328cb2bc923914bfd7ac590064f7)
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
include/block/block_int-common.h | 30 +++++++++++++++++-------------
1 file changed, 17 insertions(+), 13 deletions(-)
diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index 034c0634c8..5206f32d53 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -817,10 +817,10 @@ typedef struct BlockLimits {
int64_t max_pdiscard;
/*
- * Optimal alignment for discard requests in bytes. A power of 2
- * is best but not mandatory. Must be a multiple of
- * bl.request_alignment, and must be less than max_pdiscard if
- * that is set. May be 0 if bl.request_alignment is good enough
+ * Optimal alignment for discard requests in bytes. Note that this doesn't
+ * have to be a power of two. Must be a multiple of bl.request_alignment,
+ * and must be less than max_pdiscard if that is set. May be 0 if
+ * bl.request_alignment is good enough.
*/
uint32_t pdiscard_alignment;
@@ -831,11 +831,10 @@ typedef struct BlockLimits {
int64_t max_pwrite_zeroes;
/*
- * Optimal alignment for write zeroes requests in bytes. A power
- * of 2 is best but not mandatory. Must be a multiple of
- * bl.request_alignment, and must be less than max_pwrite_zeroes
- * if that is set. May be 0 if bl.request_alignment is good
- * enough
+ * Optimal alignment for write zeroes requests in bytes. Note that this
+ * doesn't have to be a power of two. Must be a multiple of
+ * bl.request_alignment, and must be less than max_pwrite_zeroes if that is
+ * set. May be 0 if bl.request_alignment is good enough.
*/
uint32_t pwrite_zeroes_alignment;
@@ -863,18 +862,23 @@ typedef struct BlockLimits {
uint64_t max_hw_transfer;
/*
- * Maximal number of scatter/gather elements allowed by the hardware.
+ * Maximum number of scatter/gather elements allowed by the hardware.
* Applies whenever transfers to the device bypass the kernel I/O
* scheduler, for example with SG_IO. If larger than max_iov
* or if zero, blk_get_max_hw_iov will fall back to max_iov.
*/
int max_hw_iov;
-
- /* memory alignment, in bytes so that no bounce buffer is needed */
+ /*
+ * Minimal required memory alignment in bytes for zero-copy I/O to succeed.
+ * For unaligned requests, a bounce buffer will be used.
+ */
size_t min_mem_alignment;
- /* memory alignment, in bytes, for bounce buffer */
+ /*
+ * Optimal memory alignment in bytes. This is the alignment used for any
+ * buffer allocations QEMU performs internally.
+ */
size_t opt_mem_alignment;
/* maximum number of iovec elements */
--
2.52.0

68
kvm-hw-intc-ioapic-Fix-ACCEL_KERNEL_GSI_IRQFD_POSSIBLE-t.patch Normal file
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@ -0,0 +1,68 @@
From b10f6682b2a1462efb83ba6f407d9450e82b63ac Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= <clg@redhat.com>
Date: Thu, 6 Nov 2025 11:51:48 +0100
Subject: [PATCH 5/6] hw/intc/ioapic: Fix ACCEL_KERNEL_GSI_IRQFD_POSSIBLE typo
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
RH-Author: Cédric Le Goater <clg@redhat.com>
RH-MergeRequest: 453: hw/intc/ioapic: Fix ACCEL_KERNEL_GSI_IRQFD_POSSIBLE typo
RH-Jira: RHEL-140187
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: Igor Mammedov <imammedo@redhat.com>
RH-Commit: [1/1] 2a6d42467dceb8abf7679f1b73f1491bbf67ebc1 (clegoate/qemu-kvm-centos)
Commit 638ac1c78457 introduced a regression in interrupt remapping
when running a VM configured with an intel-iommu device and an
assigned PCI VF. During boot, Linux reports repeated messages :
[ 15.416794] __common_interrupt: 2.37 No irq handler for vector
[ 15.417266] __common_interrupt: 2.37 No irq handler for vector
[ 15.417733] __common_interrupt: 2.37 No irq handler for vector
[ 15.418202] __common_interrupt: 2.37 No irq handler for vector
[ 15.418670] __common_interrupt: 2.37 No irq handler for vector
and may eventually hang.
The issue is caused by the incorrect use of the macro
ACCEL_KERNEL_GSI_IRQFD_POSSIBLE, which should instead be
ACCEL_GSI_IRQFD_POSSIBLE.
Fixes: 638ac1c78457 ("hw/intc: Generalize APIC helper names from kvm_* to accel_*")
Cc: Magnus Kulke <magnuskulke@linux.microsoft.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20251106105148.737093-1-clg@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
(cherry picked from commit 3abfbb571143ba865488b6c11f8ad75dda97d1a3)
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
hw/intc/ioapic.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/hw/intc/ioapic.c b/hw/intc/ioapic.c
index e431d00311..38e4384648 100644
--- a/hw/intc/ioapic.c
+++ b/hw/intc/ioapic.c
@@ -216,7 +216,7 @@ static void ioapic_update_kvm_routes(IOAPICCommonState *s)
#endif
}
-#ifdef ACCEL_KERNEL_GSI_IRQFD_POSSIBLE
+#ifdef ACCEL_GSI_IRQFD_POSSIBLE
static void ioapic_iec_notifier(void *private, bool global,
uint32_t index, uint32_t mask)
{
@@ -434,7 +434,7 @@ static const MemoryRegionOps ioapic_io_ops = {
static void ioapic_machine_done_notify(Notifier *notifier, void *data)
{
-#ifdef ACCEL_KERNEL_GSI_IRQFD_POSSIBLE
+#ifdef ACCEL_GSI_IRQFD_POSSIBLE
IOAPICCommonState *s = container_of(notifier, IOAPICCommonState,
machine_done);
--
2.52.0

62
kvm-q35-increase-default-tseg-size.patch Normal file
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@ -0,0 +1,62 @@
From 2b12179e5fffa2d5eba61d828eb2a3f3c96864fb Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Thu, 6 Nov 2025 11:56:40 +0100
Subject: [PATCH 6/6] q35: increase default tseg size
RH-Author: Gerd Hoffmann <kraxel@redhat.com>
RH-MergeRequest: 448: q35: increase default tseg size
RH-Jira: RHEL-139057
RH-Acked-by: Igor Mammedov <imammedo@redhat.com>
RH-Acked-by: Jon Maloy <jmaloy@redhat.com>
RH-Commit: [1/1] f69fba674307d2f1822045ddb41012d8b826724e (kraxel.rh/centos-src-qemu-kvm)
With virtual machines becoming larger (more CPUs, more memory) the
memory needed by the SMM code in OVMF to manage page tables and vcpu
state grows too.
Default SMM memory (aka TSEG) size is 16 MB, and this often is not
enough. Bump it to 64 MB for new machine types.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251106105640.1642109-1-kraxel@redhat.com>
(cherry picked from commit fa4136387928749d5a1b4fa3606ae0ce6dce75aa)
[ RHEL: drop compat property update for upstream machine types ]
[ RHEL: add compat property for rhel 9.6 + older machine types ]
Resolves: RHEL-139057
---
hw/i386/pc.c | 1 +
hw/pci-host/q35.c | 2 +-
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index dc3f140fdc..1f4154de5e 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -299,6 +299,7 @@ const size_t pc_rhel_compat_len = G_N_ELEMENTS(pc_rhel_compat);
GlobalProperty pc_rhel_9_8_compat[] = {
/* pc_rhel_10_2_compat from pc_compat_10_0 */
+ { "mch", "extended-tseg-mbytes", "16" },
{ TYPE_X86_CPU, "x-consistent-cache", "false" },
{ TYPE_X86_CPU, "x-vendor-cpuid-only-v2", "false" },
{ TYPE_X86_CPU, "x-arch-cap-always-on", "true" },
diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
index 1951ae440c..a708758d36 100644
--- a/hw/pci-host/q35.c
+++ b/hw/pci-host/q35.c
@@ -663,7 +663,7 @@ static void mch_realize(PCIDevice *d, Error **errp)
static const Property mch_props[] = {
DEFINE_PROP_UINT16("extended-tseg-mbytes", MCHPCIState, ext_tseg_mbytes,
- 16),
+ 64),
DEFINE_PROP_BOOL("smbase-smram", MCHPCIState, has_smram_at_smbase, true),
};
--
2.52.0

153
kvm-qemu-img-info-Add-cache-mode-option.patch Normal file
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@ -0,0 +1,153 @@
From e06931af04484b3900ab07f966df49dc1086734d Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Fri, 24 Oct 2025 14:30:40 +0200
Subject: [PATCH 4/6] qemu-img info: Add cache mode option
RH-Author: Kevin Wolf <kwolf@redhat.com>
RH-MergeRequest: 440: block: Expose block limits in monitor and qemu-img info
RH-Jira: RHEL-132989
RH-Acked-by: Hanna Czenczek <hreitz@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Commit: [4/4] 3b4c5546694ba39d46f18646dc1fce7a6d937e0f (kmwolf/centos-qemu-kvm)
When querying block limits, different cache modes (in particular
O_DIRECT or not) can result in different limits. Add an option to
'qemu-img info' that allows the user to specify a cache mode, so that
they can get the block limits for the cache mode they intend to use with
their VM.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20251024123041.51254-5-kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 911992fd6ec7a84c7cc82831b4bcd8a2ca5ccc76)
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
docs/tools/qemu-img.rst | 2 +-
qemu-img-cmds.hx | 4 ++--
qemu-img.c | 25 +++++++++++++++++++++----
3 files changed, 24 insertions(+), 7 deletions(-)
diff --git a/docs/tools/qemu-img.rst b/docs/tools/qemu-img.rst
index fdc9ea9cf2..558b0eb84d 100644
--- a/docs/tools/qemu-img.rst
+++ b/docs/tools/qemu-img.rst
@@ -503,7 +503,7 @@ Command description:
The size syntax is similar to :manpage:`dd(1)`'s size syntax.
-.. option:: info [--object OBJECTDEF] [--image-opts] [-f FMT] [--output=OFMT] [--backing-chain] [--limits] [-U] FILENAME
+.. option:: info [--object OBJECTDEF] [--image-opts] [-f FMT] [--output=OFMT] [--backing-chain] [--limits] [-t CACHE] [-U] FILENAME
Give information about the disk image *FILENAME*. Use it in
particular to know the size reserved on disk which can be different
diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
index 74b66f9d42..6bc8265cfb 100644
--- a/qemu-img-cmds.hx
+++ b/qemu-img-cmds.hx
@@ -66,9 +66,9 @@ SRST
ERST
DEF("info", img_info,
- "info [--object objectdef] [--image-opts] [-f fmt] [--output=ofmt] [--backing-chain] [--limits] [-U] filename")
+ "info [--object objectdef] [--image-opts] [-f fmt] [--output=ofmt] [--backing-chain] [--limits] [-t CACHE] [-U] filename")
SRST
-.. option:: info [--object OBJECTDEF] [--image-opts] [-f FMT] [--output=OFMT] [--backing-chain] [--limits] [-U] FILENAME
+.. option:: info [--object OBJECTDEF] [--image-opts] [-f FMT] [--output=OFMT] [--backing-chain] [--limits] [-t CACHE] [-U] FILENAME
ERST
DEF("map", img_map,
diff --git a/qemu-img.c b/qemu-img.c
index 5cdbeda969..a7791896c1 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -3003,6 +3003,7 @@ static gboolean str_equal_func(gconstpointer a, gconstpointer b)
static BlockGraphInfoList *collect_image_info_list(bool image_opts,
const char *filename,
const char *fmt,
+ const char *cache,
bool chain, bool limits,
bool force_share)
{
@@ -3010,6 +3011,15 @@ static BlockGraphInfoList *collect_image_info_list(bool image_opts,
BlockGraphInfoList **tail = &head;
GHashTable *filenames;
Error *err = NULL;
+ int cache_flags = 0;
+ bool writethrough = false;
+ int ret;
+
+ ret = bdrv_parse_cache_mode(cache, &cache_flags, &writethrough);
+ if (ret < 0) {
+ error_report("Invalid cache option: %s", cache);
+ return NULL;
+ }
filenames = g_hash_table_new_full(g_str_hash, str_equal_func, NULL, NULL);
@@ -3026,8 +3036,8 @@ static BlockGraphInfoList *collect_image_info_list(bool image_opts,
g_hash_table_insert(filenames, (gpointer)filename, NULL);
blk = img_open(image_opts, filename, fmt,
- BDRV_O_NO_BACKING | BDRV_O_NO_IO, false, false,
- force_share);
+ BDRV_O_NO_BACKING | BDRV_O_NO_IO | cache_flags,
+ writethrough, false, force_share);
if (!blk) {
goto err;
}
@@ -3087,6 +3097,7 @@ static int img_info(const img_cmd_t *ccmd, int argc, char **argv)
OutputFormat output_format = OFORMAT_HUMAN;
bool chain = false;
const char *filename, *fmt;
+ const char *cache = BDRV_DEFAULT_CACHE;
BlockGraphInfoList *list;
bool image_opts = false;
bool force_share = false;
@@ -3099,13 +3110,14 @@ static int img_info(const img_cmd_t *ccmd, int argc, char **argv)
{"format", required_argument, 0, 'f'},
{"image-opts", no_argument, 0, OPTION_IMAGE_OPTS},
{"backing-chain", no_argument, 0, OPTION_BACKING_CHAIN},
+ {"cache", required_argument, 0, 't'},
{"force-share", no_argument, 0, 'U'},
{"limits", no_argument, 0, OPTION_LIMITS},
{"output", required_argument, 0, OPTION_OUTPUT},
{"object", required_argument, 0, OPTION_OBJECT},
{0, 0, 0, 0}
};
- c = getopt_long(argc, argv, "hf:U", long_options, NULL);
+ c = getopt_long(argc, argv, "hf:t:U", long_options, NULL);
if (c == -1) {
break;
}
@@ -3121,6 +3133,8 @@ static int img_info(const img_cmd_t *ccmd, int argc, char **argv)
" (incompatible with -f|--format)\n"
" --backing-chain\n"
" display information about the backing chain for copy-on-write overlays\n"
+" -t, --cache CACHE\n"
+" cache mode for FILE (default: " BDRV_DEFAULT_CACHE ")\n"
" -U, --force-share\n"
" open image in shared mode for concurrent access\n"
" --limits\n"
@@ -3143,6 +3157,9 @@ static int img_info(const img_cmd_t *ccmd, int argc, char **argv)
case OPTION_BACKING_CHAIN:
chain = true;
break;
+ case 't':
+ cache = optarg;
+ break;
case 'U':
force_share = true;
break;
@@ -3164,7 +3181,7 @@ static int img_info(const img_cmd_t *ccmd, int argc, char **argv)
}
filename = argv[optind++];
- list = collect_image_info_list(image_opts, filename, fmt, chain,
+ list = collect_image_info_list(image_opts, filename, fmt, cache, chain,
limits, force_share);
if (!list) {
return 1;
--
2.52.0

240
kvm-qemu-img-info-Optionally-show-block-limits.patch Normal file
View File

@ -0,0 +1,240 @@
From f0a73f74d818259aeef128bd2a230a5db1381994 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Fri, 24 Oct 2025 14:30:39 +0200
Subject: [PATCH 3/6] qemu-img info: Optionally show block limits
RH-Author: Kevin Wolf <kwolf@redhat.com>
RH-MergeRequest: 440: block: Expose block limits in monitor and qemu-img info
RH-Jira: RHEL-132989
RH-Acked-by: Hanna Czenczek <hreitz@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Commit: [3/4] 86bbedcb5b2cfffd1da1640aff391127e87c7228 (kmwolf/centos-qemu-kvm)
Add a new --limits option to 'qemu-img info' that displays the block
limits for the image and all of its children, making the information
more accessible for human users than in QMP. This option is not enabled
by default because it can be a lot of output that isn't usually relevant
if you're not specifically trying to diagnose some I/O problem.
This makes the same information automatically also available in HMP
'info block -v'.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-ID: <20251024123041.51254-4-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 5b4b3bfdfc28d2398f34194d260d6eef9a9048b4)
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
block/qapi.c | 34 ++++++++++++++++++++++++++++++++--
docs/tools/qemu-img.rst | 6 +++++-
include/block/qapi.h | 2 +-
qemu-img-cmds.hx | 4 ++--
qemu-img.c | 15 ++++++++++++---
5 files changed, 52 insertions(+), 9 deletions(-)
diff --git a/block/qapi.c b/block/qapi.c
index 54521d0a68..9f5771e019 100644
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -417,6 +417,7 @@ fail:
*/
void bdrv_query_block_graph_info(BlockDriverState *bs,
BlockGraphInfo **p_info,
+ bool limits,
Error **errp)
{
ERRP_GUARD();
@@ -425,7 +426,7 @@ void bdrv_query_block_graph_info(BlockDriverState *bs,
BdrvChild *c;
info = g_new0(BlockGraphInfo, 1);
- bdrv_do_query_node_info(bs, qapi_BlockGraphInfo_base(info), false, errp);
+ bdrv_do_query_node_info(bs, qapi_BlockGraphInfo_base(info), limits, errp);
if (*errp) {
goto fail;
}
@@ -439,7 +440,7 @@ void bdrv_query_block_graph_info(BlockDriverState *bs,
QAPI_LIST_APPEND(children_list_tail, c_info);
c_info->name = g_strdup(c->name);
- bdrv_query_block_graph_info(c->bs, &c_info->info, errp);
+ bdrv_query_block_graph_info(c->bs, &c_info->info, limits, errp);
if (*errp) {
goto fail;
}
@@ -936,6 +937,29 @@ void bdrv_image_info_specific_dump(ImageInfoSpecific *info_spec,
visit_free(v);
}
+/**
+ * Dumps the given BlockLimitsInfo object in a human-readable form,
+ * prepending an optional prefix if the dump is not empty.
+ */
+static void bdrv_image_info_limits_dump(BlockLimitsInfo *limits,
+ const char *prefix,
+ int indentation)
+{
+ QObject *obj;
+ Visitor *v = qobject_output_visitor_new(&obj);
+
+ visit_type_BlockLimitsInfo(v, NULL, &limits, &error_abort);
+ visit_complete(v, &obj);
+ if (!qobject_is_empty_dump(obj)) {
+ if (prefix) {
+ qemu_printf("%*s%s", indentation * 4, "", prefix);
+ }
+ dump_qobject(indentation + 1, obj);
+ }
+ qobject_unref(obj);
+ visit_free(v);
+}
+
/**
* Print the given @info object in human-readable form. Every field is indented
* using the given @indentation (four spaces per indentation level).
@@ -1011,6 +1035,12 @@ void bdrv_node_info_dump(BlockNodeInfo *info, int indentation, bool protocol)
}
}
+ if (info->limits) {
+ bdrv_image_info_limits_dump(info->limits,
+ "Block limits:\n",
+ indentation);
+ }
+
if (info->has_snapshots) {
SnapshotInfoList *elem;
diff --git a/docs/tools/qemu-img.rst b/docs/tools/qemu-img.rst
index 5e7b85079d..fdc9ea9cf2 100644
--- a/docs/tools/qemu-img.rst
+++ b/docs/tools/qemu-img.rst
@@ -503,7 +503,7 @@ Command description:
The size syntax is similar to :manpage:`dd(1)`'s size syntax.
-.. option:: info [--object OBJECTDEF] [--image-opts] [-f FMT] [--output=OFMT] [--backing-chain] [-U] FILENAME
+.. option:: info [--object OBJECTDEF] [--image-opts] [-f FMT] [--output=OFMT] [--backing-chain] [--limits] [-U] FILENAME
Give information about the disk image *FILENAME*. Use it in
particular to know the size reserved on disk which can be different
@@ -571,6 +571,10 @@ Command description:
``ImageInfoSpecific*`` QAPI object (e.g. ``ImageInfoSpecificQCow2``
for qcow2 images).
+ *Block limits*
+ The block limits for I/O that QEMU detected for the image.
+ This information is only shown if the ``--limits`` option was specified.
+
.. option:: map [--object OBJECTDEF] [--image-opts] [-f FMT] [--start-offset=OFFSET] [--max-length=LEN] [--output=OFMT] [-U] FILENAME
Dump the metadata of image *FILENAME* and its backing file chain.
diff --git a/include/block/qapi.h b/include/block/qapi.h
index 54c48de26a..be554e53dc 100644
--- a/include/block/qapi.h
+++ b/include/block/qapi.h
@@ -42,7 +42,7 @@ bdrv_query_image_info(BlockDriverState *bs, ImageInfo **p_info, bool flat,
bool skip_implicit_filters, Error **errp);
void GRAPH_RDLOCK
bdrv_query_block_graph_info(BlockDriverState *bs, BlockGraphInfo **p_info,
- Error **errp);
+ bool limits, Error **errp);
void bdrv_snapshot_dump(QEMUSnapshotInfo *sn);
void bdrv_image_info_specific_dump(ImageInfoSpecific *info_spec,
diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
index 2c5a8a28f9..74b66f9d42 100644
--- a/qemu-img-cmds.hx
+++ b/qemu-img-cmds.hx
@@ -66,9 +66,9 @@ SRST
ERST
DEF("info", img_info,
- "info [--object objectdef] [--image-opts] [-f fmt] [--output=ofmt] [--backing-chain] [-U] filename")
+ "info [--object objectdef] [--image-opts] [-f fmt] [--output=ofmt] [--backing-chain] [--limits] [-U] filename")
SRST
-.. option:: info [--object OBJECTDEF] [--image-opts] [-f FMT] [--output=OFMT] [--backing-chain] [-U] FILENAME
+.. option:: info [--object OBJECTDEF] [--image-opts] [-f FMT] [--output=OFMT] [--backing-chain] [--limits] [-U] FILENAME
ERST
DEF("map", img_map,
diff --git a/qemu-img.c b/qemu-img.c
index 7a162fdc08..5cdbeda969 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -86,6 +86,7 @@ enum {
OPTION_BITMAPS = 275,
OPTION_FORCE = 276,
OPTION_SKIP_BROKEN = 277,
+ OPTION_LIMITS = 278,
};
typedef enum OutputFormat {
@@ -3002,7 +3003,8 @@ static gboolean str_equal_func(gconstpointer a, gconstpointer b)
static BlockGraphInfoList *collect_image_info_list(bool image_opts,
const char *filename,
const char *fmt,
- bool chain, bool force_share)
+ bool chain, bool limits,
+ bool force_share)
{
BlockGraphInfoList *head = NULL;
BlockGraphInfoList **tail = &head;
@@ -3039,7 +3041,7 @@ static BlockGraphInfoList *collect_image_info_list(bool image_opts,
* the chain manually here.
*/
bdrv_graph_rdlock_main_loop();
- bdrv_query_block_graph_info(bs, &info, &err);
+ bdrv_query_block_graph_info(bs, &info, limits, &err);
bdrv_graph_rdunlock_main_loop();
if (err) {
@@ -3088,6 +3090,7 @@ static int img_info(const img_cmd_t *ccmd, int argc, char **argv)
BlockGraphInfoList *list;
bool image_opts = false;
bool force_share = false;
+ bool limits = false;
fmt = NULL;
for(;;) {
@@ -3097,6 +3100,7 @@ static int img_info(const img_cmd_t *ccmd, int argc, char **argv)
{"image-opts", no_argument, 0, OPTION_IMAGE_OPTS},
{"backing-chain", no_argument, 0, OPTION_BACKING_CHAIN},
{"force-share", no_argument, 0, 'U'},
+ {"limits", no_argument, 0, OPTION_LIMITS},
{"output", required_argument, 0, OPTION_OUTPUT},
{"object", required_argument, 0, OPTION_OBJECT},
{0, 0, 0, 0}
@@ -3119,6 +3123,8 @@ static int img_info(const img_cmd_t *ccmd, int argc, char **argv)
" display information about the backing chain for copy-on-write overlays\n"
" -U, --force-share\n"
" open image in shared mode for concurrent access\n"
+" --limits\n"
+" show detected block limits (may depend on options, e.g. cache mode)\n"
" --output human|json\n"
" specify output format (default: human)\n"
" --object OBJDEF\n"
@@ -3140,6 +3146,9 @@ static int img_info(const img_cmd_t *ccmd, int argc, char **argv)
case 'U':
force_share = true;
break;
+ case OPTION_LIMITS:
+ limits = true;
+ break;
case OPTION_OUTPUT:
output_format = parse_output_format(argv[0], optarg);
break;
@@ -3156,7 +3165,7 @@ static int img_info(const img_cmd_t *ccmd, int argc, char **argv)
filename = argv[optind++];
list = collect_image_info_list(image_opts, filename, fmt, chain,
- force_share);
+ limits, force_share);
if (!list) {
return 1;
}
--
2.52.0

28
qemu-kvm.spec
View File

@ -149,7 +149,7 @@ Obsoletes: %{name}-block-ssh <= %{epoch}:%{version} \
Summary: QEMU is a machine emulator and virtualizer
Name: qemu-kvm
Version: 10.1.0
Release: 11%{?rcrel}%{?dist}%{?cc_suffix}
Release: 12%{?rcrel}%{?dist}%{?cc_suffix}
# 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)
@ -296,6 +296,18 @@ Patch75: kvm-accel-mshv-use-return-value-of-handle_pio_str_read.patch
Patch76: kvm-monitor-generalize-query-mshv-info-mshv-to-query-acc.patch
# For RHEL-138240 - QEMU crashes when stopping source VM during live migration [rhel-9]
Patch77: kvm-block-Fix-BDS-use-after-free-during-shutdown.patch
# For RHEL-132989 - Expose block limits of block nodes in QMP and qemu-img [rhel-9]
Patch78: kvm-block-Improve-comments-in-BlockLimits.patch
# For RHEL-132989 - Expose block limits of block nodes in QMP and qemu-img [rhel-9]
Patch79: kvm-block-Expose-block-limits-for-images-in-QMP.patch
# For RHEL-132989 - Expose block limits of block nodes in QMP and qemu-img [rhel-9]
Patch80: kvm-qemu-img-info-Optionally-show-block-limits.patch
# For RHEL-132989 - Expose block limits of block nodes in QMP and qemu-img [rhel-9]
Patch81: kvm-qemu-img-info-Add-cache-mode-option.patch
# For RHEL-140187 - Intel IOMMU VM freezes: "call_irq_handler: 3.37 No irq handler for vector"[rhel-9.8]
Patch82: kvm-hw-intc-ioapic-Fix-ACCEL_KERNEL_GSI_IRQFD_POSSIBLE-t.patch
# For RHEL-139057 - [qemu, rhel-9] increase default TSEG size
Patch83: kvm-q35-increase-default-tseg-size.patch
# For RHEL-11424 - [IBM 9.6 FEAT] KVM: Full boot order support - qemu part
@ -2010,6 +2022,20 @@ useradd -r -u 107 -g qemu -G kvm -d / -s /sbin/nologin \
%endif
%changelog
* Tue Jan 27 2026 Jon Maloy <jmaloy@redhat.com> - 10.1.0-12
- kvm-block-Improve-comments-in-BlockLimits.patch [RHEL-132989]
- kvm-block-Expose-block-limits-for-images-in-QMP.patch [RHEL-132989]
- kvm-qemu-img-info-Optionally-show-block-limits.patch [RHEL-132989]
- kvm-qemu-img-info-Add-cache-mode-option.patch [RHEL-132989]
- kvm-hw-intc-ioapic-Fix-ACCEL_KERNEL_GSI_IRQFD_POSSIBLE-t.patch [RHEL-140187]
- kvm-q35-increase-default-tseg-size.patch [RHEL-139057]
- Resolves: RHEL-132989
(Expose block limits of block nodes in QMP and qemu-img [rhel-9])
- Resolves: RHEL-140187
(Intel IOMMU VM freezes: "call_irq_handler: 3.37 No irq handler for vector"[rhel-9.8])
- Resolves: RHEL-139057
([qemu, rhel-9] increase default TSEG size)
* Mon Jan 19 2026 Jon Maloy <jmaloy@redhat.com> - 10.1.0-11
- kvm-block-Fix-BDS-use-after-free-during-shutdown.patch [RHEL-138240]
- Resolves: RHEL-138240