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qemu: Enable I/O APIC even more frequently

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In my previous commit v10.10.0-48-g2d222ecf6e I've made us enable
I/O APIC when there is an IOMMU with EIM. This works well. What
does not work is case when there's just an IOMMU without EIM but
with 256+ vCPUS. Problem is that post parsing happens in two
stages: general domain post parse (where
qemuDomainDefEnableDefaultFeatures() is called) and then per
device post parse (where qemuDomainIOMMUDefPostParse() is
called). Now, in aforementioned case it is the device post parse
phase where EIM is enabled but the code that would enable
VIR_DOMAIN_FEATURE_IOAPIC has already run.

To resolve this, make the domain post parse callback "foresee"
the future enabling of EIM so that it can turn on I/O APIC
beforehand.

Resolves: https://issues.redhat.com/browse/RHEL-65844
Fixes: 2d222ecf6e73614a400b830ac56e9aaa1bc55ecc
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
This commit is contained in:
Michal Privoznik 2024-12-18 11:07:26 +01:00
parent ef7c0f46f9
commit 0162f2008e
5 changed files with 51 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
src/qemu/qemu_postparse.c
View File

@ -783,6 +783,15 @@ qemuDomainPstoreDefPostParse(virDomainPstoreDef *pstore,
}
static bool
qemuDomainNeedsIOMMUWithEIM(const virDomainDef *def)
{
return ARCH_IS_X86(def->os.arch) &&
virDomainDefGetVcpusMax(def) > QEMU_MAX_VCPUS_WITHOUT_EIM &&
qemuDomainIsQ35(def);
}
static int
qemuDomainIOMMUDefPostParse(virDomainIOMMUDef *iommu,
const virDomainDef *def,
@ -793,9 +802,7 @@ qemuDomainIOMMUDefPostParse(virDomainIOMMUDef *iommu,
* (EIM) is not explicitly turned off, let's enable it. If we didn't then
* guest will have troubles with interrupts. */
if (parseFlags & VIR_DOMAIN_DEF_PARSE_ABI_UPDATE &&
ARCH_IS_X86(def->os.arch) &&
virDomainDefGetVcpusMax(def) > QEMU_MAX_VCPUS_WITHOUT_EIM &&
qemuDomainIsQ35(def) &&
qemuDomainNeedsIOMMUWithEIM(def) &&
iommu && iommu->model == VIR_DOMAIN_IOMMU_MODEL_INTEL) {
/* eim requires intremap. */
@ -1548,9 +1555,13 @@ qemuDomainDefEnableDefaultFeatures(virDomainDef *def,
def->features[VIR_DOMAIN_FEATURE_GIC] = VIR_TRISTATE_SWITCH_ON;
}
/* IOMMU with intremap requires split I/O APIC */
/* IOMMU with intremap requires split I/O APIC. But it may happen that
* domain already has IOMMU without inremap. This will be fixed in
* qemuDomainIOMMUDefPostParse() but there domain definition can't be
* modified so change it now. */
if (def->iommu &&
def->iommu->intremap == VIR_TRISTATE_SWITCH_ON &&
(def->iommu->intremap == VIR_TRISTATE_SWITCH_ON ||
qemuDomainNeedsIOMMUWithEIM(def)) &&
def->features[VIR_DOMAIN_FEATURE_IOAPIC] == VIR_DOMAIN_IOAPIC_NONE) {
def->features[VIR_DOMAIN_FEATURE_IOAPIC] = VIR_DOMAIN_IOAPIC_QEMU;
}

1
tests/qemuxmlconfdata/intel-iommu-eim-autoadd-v2.x86_64-latest.abi-update.args Symbolic link
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@ -0,0 +1 @@
intel-iommu-eim-autoadd.x86_64-latest.abi-update.args

1
tests/qemuxmlconfdata/intel-iommu-eim-autoadd-v2.x86_64-latest.abi-update.xml Symbolic link
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@ -0,0 +1 @@
intel-iommu-eim-autoadd.x86_64-latest.abi-update.xml

32
tests/qemuxmlconfdata/intel-iommu-eim-autoadd-v2.xml Normal file
View File

@ -0,0 +1,32 @@
<domain type='kvm'>
<name>QEMUGuest1</name>
<uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
<memory unit='KiB'>219100</memory>
<currentMemory unit='KiB'>219100</currentMemory>
<vcpu placement='static'>288</vcpu>
<os>
<type arch='x86_64' machine='q35'>hvm</type>
<boot dev='hd'/>
</os>
<cpu mode='custom' match='exact' check='none'>
<model fallback='forbid'>qemu64</model>
</cpu>
<clock offset='utc'/>
<on_poweroff>destroy</on_poweroff>
<on_reboot>restart</on_reboot>
<on_crash>destroy</on_crash>
<devices>
<emulator>/usr/bin/qemu-system-x86_64</emulator>
<controller type='pci' index='0' model='pcie-root'/>
<controller type='usb' index='0' model='none'/>
<controller type='sata' index='0'>
<address type='pci' domain='0x0000' bus='0x00' slot='0x1f' function='0x2'/>
</controller>
<input type='mouse' bus='ps2'/>
<input type='keyboard' bus='ps2'/>
<iommu model="intel"/>
<audio id='1' type='none'/>
<watchdog model='itco' action='reset'/>
<memballoon model='none'/>
</devices>
</domain>

1
tests/qemuxmlconftest.c
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@ -2774,6 +2774,7 @@ mymain(void)
DO_TEST_CAPS_LATEST("intel-iommu-dma-translation");
DO_TEST_CAPS_LATEST_PARSE_ERROR("intel-iommu-wrong-machine");
DO_TEST_CAPS_LATEST_ABI_UPDATE("intel-iommu-eim-autoadd");
DO_TEST_CAPS_LATEST_ABI_UPDATE("intel-iommu-eim-autoadd-v2");
DO_TEST_CAPS_ARCH_LATEST("iommu-smmuv3", "aarch64");
DO_TEST_CAPS_LATEST("virtio-iommu-x86_64");
DO_TEST_CAPS_VER_PARSE_ERROR("virtio-iommu-x86_64", "6.1.0");