From: Lu Baolu <baolu.lu@linux.intel.com> To: Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org> Cc: Ashok Raj <ashok.raj@intel.com>, Jacob Pan <jacob.jun.pan@linux.intel.com>, Kevin Tian <kevin.tian@intel.com>, Liu Yi L <yi.l.liu@intel.com>, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Lu Baolu <baolu.lu@linux.intel.com> Subject: [PATCH v2 2/2] iommu/vt-d: Use INVALID response code instead of FAILURE Date: Tue, 26 Jan 2021 16:07:30 +0800 [thread overview] Message-ID: <20210126080730.2232859-3-baolu.lu@linux.intel.com> (raw) In-Reply-To: <20210126080730.2232859-1-baolu.lu@linux.intel.com> The VT-d IOMMU response RESPONSE_FAILURE for a page request in below cases: - When it gets a Page_Request with no PASID; - When it gets a Page_Request with PASID that is not in use for this device. This is allowed by the spec, but IOMMU driver doesn't support such cases today. When the device receives RESPONSE_FAILURE, it sends the device state machine to HALT state. Now if we try to unload the driver, it hangs since the device doesn't send any outbound transactions to host when the driver is trying to clear things up. The only possible responses would be for invalidation requests. Let's use RESPONSE_INVALID instead for now, so that the device state machine doesn't enter HALT state. Suggested-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> --- drivers/iommu/intel/svm.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c index d7c98c5fa4e7..574a7e657a9a 100644 --- a/drivers/iommu/intel/svm.c +++ b/drivers/iommu/intel/svm.c @@ -911,10 +911,8 @@ static irqreturn_t prq_event_thread(int irq, void *d) u64 address; handled = 1; - req = &iommu->prq[head / sizeof(*req)]; - - result = QI_RESP_FAILURE; + result = QI_RESP_INVALID; address = (u64)req->addr << VTD_PAGE_SHIFT; if (!req->pasid_present) { pr_err("%s: Page request without PASID: %08llx %08llx\n", @@ -952,7 +950,6 @@ static irqreturn_t prq_event_thread(int irq, void *d) rcu_read_unlock(); } - result = QI_RESP_INVALID; /* Since we're using init_mm.pgd directly, we should never take * any faults on kernel addresses. */ if (!svm->mm) -- 2.25.1
WARNING: multiple messages have this Message-ID (diff)
From: Lu Baolu <baolu.lu@linux.intel.com> To: Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org> Cc: Kevin Tian <kevin.tian@intel.com>, Ashok Raj <ashok.raj@intel.com>, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org Subject: [PATCH v2 2/2] iommu/vt-d: Use INVALID response code instead of FAILURE Date: Tue, 26 Jan 2021 16:07:30 +0800 [thread overview] Message-ID: <20210126080730.2232859-3-baolu.lu@linux.intel.com> (raw) In-Reply-To: <20210126080730.2232859-1-baolu.lu@linux.intel.com> The VT-d IOMMU response RESPONSE_FAILURE for a page request in below cases: - When it gets a Page_Request with no PASID; - When it gets a Page_Request with PASID that is not in use for this device. This is allowed by the spec, but IOMMU driver doesn't support such cases today. When the device receives RESPONSE_FAILURE, it sends the device state machine to HALT state. Now if we try to unload the driver, it hangs since the device doesn't send any outbound transactions to host when the driver is trying to clear things up. The only possible responses would be for invalidation requests. Let's use RESPONSE_INVALID instead for now, so that the device state machine doesn't enter HALT state. Suggested-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> --- drivers/iommu/intel/svm.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c index d7c98c5fa4e7..574a7e657a9a 100644 --- a/drivers/iommu/intel/svm.c +++ b/drivers/iommu/intel/svm.c @@ -911,10 +911,8 @@ static irqreturn_t prq_event_thread(int irq, void *d) u64 address; handled = 1; - req = &iommu->prq[head / sizeof(*req)]; - - result = QI_RESP_FAILURE; + result = QI_RESP_INVALID; address = (u64)req->addr << VTD_PAGE_SHIFT; if (!req->pasid_present) { pr_err("%s: Page request without PASID: %08llx %08llx\n", @@ -952,7 +950,6 @@ static irqreturn_t prq_event_thread(int irq, void *d) rcu_read_unlock(); } - result = QI_RESP_INVALID; /* Since we're using init_mm.pgd directly, we should never take * any faults on kernel addresses. */ if (!svm->mm) -- 2.25.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2021-01-26 17:47 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-01-26 8:07 [PATCH v2 0/2] iommu/vt-d: Some misc tweaks in SVA Lu Baolu 2021-01-26 8:07 ` Lu Baolu 2021-01-26 8:07 ` [PATCH v2 1/2] iommu/vt-d: Clear PRQ overflow only when PRQ is empty Lu Baolu 2021-01-26 8:07 ` Lu Baolu 2021-01-26 8:07 ` Lu Baolu [this message] 2021-01-26 8:07 ` [PATCH v2 2/2] iommu/vt-d: Use INVALID response code instead of FAILURE Lu Baolu 2021-01-29 8:25 ` [PATCH v2 0/2] iommu/vt-d: Some misc tweaks in SVA Joerg Roedel
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