From: Wei Huang wei.huang2@amd.com
[ 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@amd.com Co-developed-by: Suravee Suthikulpanit suravee.suthikulpanit@amd.com Signed-off-by: Suravee Suthikulpanit suravee.suthikulpanit@amd.com Link: https://lore.kernel.org/r/20210820202957.187572-2-suravee.suthikulpanit@amd.... Link: https://lore.kernel.org/r/20210820202957.187572-3-suravee.suthikulpanit@amd.... Fixes: 8bda0cfbdc1a ("iommu/amd: Detect and initialize guest vAPIC log") Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iommu/amd/init.c | 31 ++++++++++++++++++++++++------- 1 file changed, 24 insertions(+), 7 deletions(-)
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c index fa57986c2309..28de889aa516 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 */
@@ -2396,6 +2405,14 @@ 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