Re: [PATCH] qemu: Enable I/O APIC even more frequently

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(a)redhat.com&gt; --- src/qemu/qemu_postparse.c | 21 +++++++++--- ...m-autoadd-v2.x86_64-latest.abi-update.args | 1 + ...im-autoadd-v2.x86_64-latest.abi-update.xml | 1 + .../intel-iommu-eim-autoadd-v2.xml | 32 +++++++++++++++++++ tests/qemuxmlconftest.c | 1 + 5 files changed, 51 insertions(+), 5 deletions(-) create mode 120000 tests/qemuxmlconfdata/intel-iommu-eim-autoadd-v2.x86_64-latest.abi-update.args create mode 120000 tests/qemuxmlconfdata/intel-iommu-eim-autoadd-v2.x86_64-latest.abi-update.xml create mode 100644 tests/qemuxmlconfdata/intel-iommu-eim-autoadd-v2.xml diff --git a/src/qemu/qemu_postparse.c b/src/qemu/qemu_postparse.c index 4fbd849ebf..34b95ece1b 100644 --- a/src/qemu/qemu_postparse.c +++ b/src/qemu/qemu_postparse.c @@ -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,