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* Tue Nov 01 2022 Miroslav Rezanina <mrezanin@redhat.com> - 7.1.0-4

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- kvm-Revert-intel_iommu-Fix-irqchip-X2APIC-configuration-.patch [bz#2126095]
- Resolves: bz#2126095
  ([rhel9.2][intel_iommu]Booting guest with "-device intel-iommu,intremap=on,device-iotlb=on,caching-mode=on" causes kernel call trace)
This commit is contained in:
Miroslav Rezanina 2022-11-01 06:30:42 -04:00
parent afd495b342
commit 3e616168bc
2 changed files with 92 additions and 1 deletions
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84
kvm-Revert-intel_iommu-Fix-irqchip-X2APIC-configuration-.patch Normal file
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@ -0,0 +1,84 @@
From 7f5289f426b25cf1113a450a3aa311170ac30397 Mon Sep 17 00:00:00 2001
From: Peter Xu <peterx@redhat.com>
Date: Mon, 26 Sep 2022 11:32:06 -0400
Subject: [PATCH] Revert "intel_iommu: Fix irqchip / X2APIC configuration
checks"
RH-Author: Peter Xu <peterx@redhat.com>
RH-MergeRequest: 121: Revert "intel_iommu: Fix irqchip / X2APIC configuration checks"
RH-Bugzilla: 2126095
RH-Acked-by: Igor Mammedov <imammedo@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Acked-by: Jason Wang <jasowang@redhat.com>
RH-Commit: [1/1] 6218c5f81c205ab160f4ccdb203ae39d4af3339e (peterx/qemu-kvm)
It's true that when vcpus<=255 we don't require the length of 32bit APIC
IDs. However here since we already have EIM=ON it means the hypervisor
will declare the VM as x2apic supported (e.g. VT-d ECAP register will have
EIM bit 4 set), so the guest should assume the APIC IDs are 32bits width
even if vcpus<=255. In short, commit 77250171bdc breaks any simple cmdline
that wants to boot a VM with >=9 but <=255 vcpus with:
-device intel-iommu,intremap=on
For anyone who does not want to enable x2apic, we can use eim=off in the
intel-iommu parameters to skip enabling KVM x2apic.
This partly reverts commit 77250171bdc02aee106083fd2a068147befa1a38, while
keeping the valid bit on checking split irqchip, but revert the other change.
One thing to mention is that this patch may break migration compatibility
of such VM, however that's probably the best thing we can do, because the
old behavior was simply wrong and not working for >8 vcpus. For <=8 vcpus,
there could be a light guest ABI change (by enabling KVM x2apic after this
patch), but logically it shouldn't affect the migration from working.
Also, this is not the 1st commit to change x2apic behavior. Igor provided
a full history of how this evolved for the past few years:
https://lore.kernel.org/qemu-devel/20220922154617.57d1a1fb@redhat.com/
Relevant commits for reference:
fb506e701e ("intel_iommu: reject broken EIM", 2016-10-17)
c1bb5418e3 ("target/i386: Support up to 32768 CPUs without IRQ remapping", 2020-12-10)
77250171bd ("intel_iommu: Fix irqchip / X2APIC configuration checks", 2022-05-16)
dc89f32d92 ("target/i386: Fix sanity check on max APIC ID / X2APIC enablement", 2022-05-16)
We may want to have this for stable too (mostly for 7.1.0 only). Adding a
fixes tag.
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Claudio Fontana <cfontana@suse.de>
Cc: Igor Mammedov <imammedo@redhat.com>
Fixes: 77250171bd ("intel_iommu: Fix irqchip / X2APIC configuration checks")
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20220926153206.10881-1-peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
(cherry picked from commit 20ca47429e96df84e7b2e741f740bfce8a813fb2)
Signed-off-by: Peter Xu <peterx@redhat.com>
---
hw/i386/intel_iommu.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 05d53a1aa9..6524c2ee32 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -3818,6 +3818,11 @@ static bool vtd_decide_config(IntelIOMMUState *s, Error **errp)
error_setg(errp, "eim=on requires accel=kvm,kernel-irqchip=split");
return false;
}
+ if (!kvm_enable_x2apic()) {
+ error_setg(errp, "eim=on requires support on the KVM side"
+ "(X2APIC_API, first shipped in v4.7)");
+ return false;
+ }
}
/* Currently only address widths supported are 39 and 48 bits */
--
2.31.1

9
qemu-kvm.spec
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@ -151,7 +151,7 @@ Obsoletes: %{name}-block-ssh <= %{epoch}:%{version} \
Summary: QEMU is a machine emulator and virtualizer
Name: qemu-kvm
Version: 7.1.0
Release: 3%{?rcrel}%{?dist}%{?cc_suffix}
Release: 4%{?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)
@ -249,6 +249,8 @@ Patch45: kvm-i386-do-kvm_put_msr_feature_control-first-thing-when.patch
Patch46: kvm-Revert-Re-enable-capstone-internal-build.patch
# For bz#2108531 - Windows guest reboot after migration with wsl2 installed inside
Patch47: kvm-target-i386-kvm-fix-kvmclock_current_nsec-Assertion-.patch
# For bz#2126095 - [rhel9.2][intel_iommu]Booting guest with "-device intel-iommu,intremap=on,device-iotlb=on,caching-mode=on" causes kernel call trace
Patch48: kvm-Revert-intel_iommu-Fix-irqchip-X2APIC-configuration-.patch
%if %{have_clang}
BuildRequires: clang
@ -1281,6 +1283,11 @@ useradd -r -u 107 -g qemu -G kvm -d / -s /sbin/nologin \
%endif
%changelog
* Tue Nov 01 2022 Miroslav Rezanina <mrezanin@redhat.com> - 7.1.0-4
- kvm-Revert-intel_iommu-Fix-irqchip-X2APIC-configuration-.patch [bz#2126095]
- Resolves: bz#2126095
([rhel9.2][intel_iommu]Booting guest with "-device intel-iommu,intremap=on,device-iotlb=on,caching-mode=on" causes kernel call trace)
* Thu Oct 13 2022 Jon Maloy <jmaloy@redhat.com> - 7.1.0-3
- kvm-target-i386-kvm-fix-kvmclock_current_nsec-Assertion-.patch [bz#2108531]
- Resolves: bz#2108531