This is a note to let you know that I've just added the patch titled
iommu/amd: Relocate GAMSup check to early_enable_iommus
to the 5.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
iommu-amd-relocate-gamsup-check-to-early_enable_iomm.patch
and it can be found in the queue-5.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit fa156cbcb66b2f74eea256157d7ff76fb996a57e
Author: Wei Huang <wei.huang2@xxxxxxx>
Date: Fri Aug 20 15:29:55 2021 -0500
iommu/amd: Relocate GAMSup check to early_enable_iommus
[ Upstream commit c3811a50addd23b9bb5a36278609ee1638debcf6 ]
Currently, iommu_init_ga() checks and disables IOMMU VAPIC support
(i.e. AMD AVIC support in IOMMU) when GAMSup feature bit is not set.
However it forgets to clear IRQ_POSTING_CAP from the previously set
amd_iommu_irq_ops.capability.
This triggers an invalid page fault bug during guest VM warm reboot
if AVIC is enabled since the irq_remapping_cap(IRQ_POSTING_CAP) is
incorrectly set, and crash the system with the following kernel trace.
BUG: unable to handle page fault for address: 0000000000400dd8
RIP: 0010:amd_iommu_deactivate_guest_mode+0x19/0xbc
Call Trace:
svm_set_pi_irte_mode+0x8a/0xc0 [kvm_amd]
? kvm_make_all_cpus_request_except+0x50/0x70 [kvm]
kvm_request_apicv_update+0x10c/0x150 [kvm]
svm_toggle_avic_for_irq_window+0x52/0x90 [kvm_amd]
svm_enable_irq_window+0x26/0xa0 [kvm_amd]
vcpu_enter_guest+0xbbe/0x1560 [kvm]
? avic_vcpu_load+0xd5/0x120 [kvm_amd]
? kvm_arch_vcpu_load+0x76/0x240 [kvm]
? svm_get_segment_base+0xa/0x10 [kvm_amd]
kvm_arch_vcpu_ioctl_run+0x103/0x590 [kvm]
kvm_vcpu_ioctl+0x22a/0x5d0 [kvm]
__x64_sys_ioctl+0x84/0xc0
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xae
Fixes by moving the initializing of AMD IOMMU interrupt remapping mode
(amd_iommu_guest_ir) earlier before setting up the
amd_iommu_irq_ops.capability with appropriate IRQ_POSTING_CAP flag.
[joro: Squashed the two patches and limited
check_features_on_all_iommus() to CONFIG_IRQ_REMAP
to fix a compile warning.]
Signed-off-by: Wei Huang <wei.huang2@xxxxxxx>
Co-developed-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
Link: https://lore.kernel.org/r/20210820202957.187572-2-suravee.suthikulpanit@xxxxxxx
Link: https://lore.kernel.org/r/20210820202957.187572-3-suravee.suthikulpanit@xxxxxxx
Fixes: 8bda0cfbdc1a ("iommu/amd: Detect and initialize guest vAPIC log")
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index 46280e6e1535..5c21f1ee5098 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -298,6 +298,22 @@ int amd_iommu_get_num_iommus(void)
return amd_iommus_present;
}
+#ifdef CONFIG_IRQ_REMAP
+static bool check_feature_on_all_iommus(u64 mask)
+{
+ bool ret = false;
+ struct amd_iommu *iommu;
+
+ for_each_iommu(iommu) {
+ ret = iommu_feature(iommu, mask);
+ if (!ret)
+ return false;
+ }
+
+ return true;
+}
+#endif
+
/*
* For IVHD type 0x11/0x40, EFR is also available via IVHD.
* Default to IVHD EFR since it is available sooner
@@ -854,13 +870,6 @@ static int iommu_init_ga(struct amd_iommu *iommu)
int ret = 0;
#ifdef CONFIG_IRQ_REMAP
- /* Note: We have already checked GASup from IVRS table.
- * Now, we need to make sure that GAMSup is set.
- */
- if (AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir) &&
- !iommu_feature(iommu, FEATURE_GAM_VAPIC))
- amd_iommu_guest_ir = AMD_IOMMU_GUEST_IR_LEGACY_GA;
-
ret = iommu_init_ga_log(iommu);
#endif /* CONFIG_IRQ_REMAP */
@@ -2477,6 +2486,14 @@ static void early_enable_iommus(void)
}
#ifdef CONFIG_IRQ_REMAP
+ /*
+ * Note: We have already checked GASup from IVRS table.
+ * Now, we need to make sure that GAMSup is set.
+ */
+ if (AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir) &&
+ !check_feature_on_all_iommus(FEATURE_GAM_VAPIC))
+ amd_iommu_guest_ir = AMD_IOMMU_GUEST_IR_LEGACY_GA;
+
if (AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir))
amd_iommu_irq_ops.capability |= (1 << IRQ_POSTING_CAP);
#endif
