Messages in this thread Patch in this message | | | From | Suravee Suthikulpanit <> | Subject | [PATCH 2/3] iommu/amd: Relocate GAMSup check to early_enable_iommus | Date | Fri, 20 Aug 2021 15:29:56 -0500 |
| |
From: Wei Huang <wei.huang2@amd.com>
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.
Signed-off-by: Wei Huang <wei.huang2@amd.com> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> --- drivers/iommu/amd/init.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c index c97961451ac5..ea3330ed545d 100644 --- a/drivers/iommu/amd/init.c +++ b/drivers/iommu/amd/init.c @@ -867,13 +867,6 @@ 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 */ @@ -2490,6 +2483,14 @@ 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 -- 2.17.1
| |