Messages in this thread | | | Subject | Re: [PATCH] iommu/amd: fix interrupt remapping for avic | From | Suravee Suthikulpanit <> | Date | Wed, 16 Sep 2020 17:38:09 +0700 |
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On 9/15/20 8:19 PM, Joao Martins wrote: > On 9/15/20 1:30 PM, Suravee Suthikulpanit wrote: >> On 9/15/20 6:25 PM, Maxim Levitsky wrote: >>> On Mon, 2020-09-14 at 21:48 +0700, Suravee Suthikulpanit wrote: >>>> Could you please try with the following patch instead? >>>> >>>> --- a/drivers/iommu/amd/iommu.c >>>> +++ b/drivers/iommu/amd/iommu.c >>>> @@ -3840,14 +3840,18 @@ int amd_iommu_activate_guest_mode(void *data) >>>> { >>>> struct amd_ir_data *ir_data = (struct amd_ir_data *)data; >>>> struct irte_ga *entry = (struct irte_ga *) ir_data->entry; >>>> + u64 valid; >>>> >>>> if (!AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir) || >>>> !entry || entry->lo.fields_vapic.guest_mode) >>>> return 0; >>>> >>>> + valid = entry->lo.fields_vapic.valid; >>>> + >>>> entry->lo.val = 0; >>>> entry->hi.val = 0; >>>> >>>> + entry->lo.fields_vapic.valid = valid; >>>> entry->lo.fields_vapic.guest_mode = 1; >>>> entry->lo.fields_vapic.ga_log_intr = 1; >>>> entry->hi.fields.ga_root_ptr = ir_data->ga_root_ptr; >>>> @@ -3864,12 +3868,14 @@ int amd_iommu_deactivate_guest_mode(void *data) >>>> struct amd_ir_data *ir_data = (struct amd_ir_data *)data; >>>> struct irte_ga *entry = (struct irte_ga *) ir_data->entry; >>>> struct irq_cfg *cfg = ir_data->cfg; >>>> - u64 valid = entry->lo.fields_remap.valid; >>>> + u64 valid; >>>> >>>> if (!AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir) || >>>> !entry || !entry->lo.fields_vapic.guest_mode) >>>> return 0; >>>> >>>> + valid = entry->lo.fields_remap.valid; >>>> + >>>> entry->lo.val = 0; >>>> entry->hi.val = 0; >>> I see. I based my approach on the fact that valid bit was >>> set always to true anyway before, plus that amd_iommu_activate_guest_mode >>> should be really only called when someone activates a valid interrupt remapping >>> entry, but IMHO the approach of preserving the valid bit is safer anyway. >>> >>> It works on my system (I applied the patch manually, since either your or my email client, >>> seems to mangle the patch) >>> >> >> Sorry for the mangled patch. I'll submit the patch w/ your information. Thanks for your help reporting, debugging, and >> testing the patch. >> > I assume you're only doing the valid bit preservation in amd_iommu_activate_guest_mode() ? > The null deref fix in amd_iommu_deactivate_guest_mode() was fixed elsewhere[0], or are you > planning on merging both changes like the diff you attached?
I am planning to send a separate patch just for amd_iommu_activate_guest_mode().
> Asking also because commit 26e495f341 ("iommu/amd: Restore IRTE.RemapEn bit after > programming IRTE") was added in v5.4 and v5.8 stable trees but the v5.4 backport didn't > include e52d58d54a321 ("iommu/amd: Use cmpxchg_double() when updating 128-bit IRTE").
We should probably backport the e52d58d54a321 along with the fixes in amd_iommu_activate_guest_mode() and amd_iommu_deactivate_guest_mode(). I'll work with the community to get these back-ported.
Thanks, Suravee
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