[{"id":3680790,"web_url":"http://patchwork.ozlabs.org/comment/3680790/","msgid":"","list_archive_url":null,"date":"2026-04-22T18:22:01","subject":"ACK: [SRU][Q][PATCH 0/1] Revert \"iommu: disable SVA when CONFIG_X86\n is set\"","submitter":{"id":89903,"url":"http://patchwork.ozlabs.org/api/people/89903/","name":"Tim Whisonant","email":"tim.whisonant@canonical.com"},"content":"On Wed, Apr 22, 2026 at 09:07:52PM +0300, Mehmet Basaran wrote:\n> BugLink: https://bugs.launchpad.net/bugs/2149766\n> \n> [Impact]\n> \n> The issue has been brought to our attention when questing (6.17)\n> kernels were unable to load amd_xdna drivers. However, this commit,\n> in addition to NPUs, also affects PCIe cards which make use of\n> unified memory (GPUs, Accelerators, NICs). With this commit, PCIe\n> devices will revert to using legacy method (pinning) instead of\n> unified memory. As a result,\n> - arguably it will be less secure,\n> - there can be performance drops.\n> \n> Currently, this commit is part of an 8 commit patch series:\n> \"Fix stale IOTLB entries for kernel address space\", v7.\n> [PATCH v7 1/8] iommu: Disable SVA when CONFIG_X86 is set\n> [PATCH v7 2/8] mm: Add a ptdesc flag to mark kernel page tables\n> [PATCH v7 3/8] mm: Actually mark kernel page table pages\n> [PATCH v7 4/8] x86/mm: Use 'ptdesc' when freeing PMD pages\n> [PATCH v7 5/8] mm: Introduce pure page table freeing function\n> [PATCH v7 6/8] x86/mm: Use pagetable_free()\n> [PATCH v7 7/8] mm: Introduce deferred freeing for kernel page tables\n> [PATCH v7 8/8] iommu/sva: Invalidate stale IOTLB entries for kernel address space\n> \n> where \"iommu: disable SVA when CONFIG_X86 is set\" is undone by\n> the 8th commit. We only have this commit from the whole patchset.\n> Ideally we should have the whole patchset applied.\n> \n> [Fix]\n> \n> This commit fixes the following issue which is old,\n> 26b25a2b98e4 (\"iommu: Bind process address spaces to devices\")\n> and we applied this commit recently. So, reverting this commit\n> won't be introducing regressions. Affected kernel versions are:\n> - 6.8 due to the reasons above.\n> - 6.17 due to both the reasons above and the amd_xdna issue.\n> \n> [Test Plan]\n> \n> Our regression test suite doesn't catch this issue. However,\n> we will run it again to see it doesn't cause anything else.\n> \n> [Where problems could occur]\n> \n> Reverted commit is a fix for a security vulnerability related to\n> IOMMU Shared Virtual Addressing (SVA). In an SVA context, an \n> IOMMU can cache kernel page table entries. When a kernel page \n> table page is freed and reallocated for another purpose, the \n> IOMMU might still hold stale, incorrect entries. This can be \n> exploited to cause a use-after-free or write-after-free condition,\n> potentially leading to privilege escalation or data corruption.\n> \n> Mehmet Basaran (1):\n> Revert \"iommu: disable SVA when CONFIG_X86 is set\"\n> \n> drivers/iommu/iommu-sva.c | 3 ---\n> 1 file changed, 3 deletions(-)\n> \n> -- \n> 2.43.0\n> \n\nAcked-by: Tim Whisonant ","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=fail reason=\"signature verification failed\" (4096-bit key;\n unprotected) header.d=canonical.com header.i=@canonical.com\n header.a=rsa-sha256 header.s=20251003 header.b=ML6q3ObU;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=lists.ubuntu.com\n (client-ip=185.125.189.65; helo=lists.ubuntu.com;\n envelope-from=kernel-team-bounces@lists.ubuntu.com;\n receiver=patchwork.ozlabs.org)"],"Received":["from lists.ubuntu.com (lists.ubuntu.com [185.125.189.65])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g16yG0lTDz1y2d\n\tfor ; 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charset=\"utf-8\"","Content-Transfer-Encoding":"base64","Errors-To":"kernel-team-bounces@lists.ubuntu.com","Sender":"\"kernel-team\" "}},{"id":3680810,"web_url":"http://patchwork.ozlabs.org/comment/3680810/","msgid":"","list_archive_url":null,"date":"2026-04-22T18:37:55","subject":"ACK: [SRU][Q][PATCH 0/1] Revert \"iommu: disable SVA when CONFIG_X86\n is set\"","submitter":{"id":91410,"url":"http://patchwork.ozlabs.org/api/people/91410/","name":"Alice C. Munduruca","email":"alice.munduruca@canonical.com"},"content":"On Wed Apr 22, 2026 at 2:07 PM EDT, Mehmet Basaran wrote:\n> BugLink: https://bugs.launchpad.net/bugs/2149766\n>\n> [Impact]\n> \n> The issue has been brought to our attention when questing (6.17)\n> kernels were unable to load amd_xdna drivers. However, this commit,\n> in addition to NPUs, also affects PCIe cards which make use of\n> unified memory (GPUs, Accelerators, NICs). With this commit, PCIe\n> devices will revert to using legacy method (pinning) instead of\n> unified memory. As a result,\n> - arguably it will be less secure,\n> - there can be performance drops.\n>\n> Currently, this commit is part of an 8 commit patch series:\n> \"Fix stale IOTLB entries for kernel address space\", v7.\n> [PATCH v7 1/8] iommu: Disable SVA when CONFIG_X86 is set\n> [PATCH v7 2/8] mm: Add a ptdesc flag to mark kernel page tables\n> [PATCH v7 3/8] mm: Actually mark kernel page table pages\n> [PATCH v7 4/8] x86/mm: Use 'ptdesc' when freeing PMD pages\n> [PATCH v7 5/8] mm: Introduce pure page table freeing function\n> [PATCH v7 6/8] x86/mm: Use pagetable_free()\n> [PATCH v7 7/8] mm: Introduce deferred freeing for kernel page tables\n> [PATCH v7 8/8] iommu/sva: Invalidate stale IOTLB entries for kernel address space\n>\n> where \"iommu: disable SVA when CONFIG_X86 is set\" is undone by\n> the 8th commit. We only have this commit from the whole patchset.\n> Ideally we should have the whole patchset applied.\n>\n> [Fix]\n>\n> This commit fixes the following issue which is old,\n> 26b25a2b98e4 (\"iommu: Bind process address spaces to devices\")\n> and we applied this commit recently. So, reverting this commit\n> won't be introducing regressions. Affected kernel versions are:\n> - 6.8 due to the reasons above.\n> - 6.17 due to both the reasons above and the amd_xdna issue.\n>\n> [Test Plan]\n>\n> Our regression test suite doesn't catch this issue. However,\n> we will run it again to see it doesn't cause anything else.\n>\n> [Where problems could occur]\n>\n> Reverted commit is a fix for a security vulnerability related to\n> IOMMU Shared Virtual Addressing (SVA). In an SVA context, an \n> IOMMU can cache kernel page table entries. When a kernel page \n> table page is freed and reallocated for another purpose, the \n> IOMMU might still hold stale, incorrect entries. This can be \n> exploited to cause a use-after-free or write-after-free condition,\n> potentially leading to privilege escalation or data corruption.\n>\n> Mehmet Basaran (1):\n> Revert \"iommu: disable SVA when CONFIG_X86 is set\"\n>\n> drivers/iommu/iommu-sva.c | 3 ---\n> 1 file changed, 3 deletions(-)\n\nAcked-by: Alice C. 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Munduruca\" ","X-Mailer":"aerc 0.21.0","References":"<20260422180753.338056-1-mehmet.basaran@canonical.com>","In-Reply-To":"<20260422180753.338056-1-mehmet.basaran@canonical.com>","X-BeenThere":"kernel-team@lists.ubuntu.com","X-Mailman-Version":"2.1.20","Precedence":"list","List-Id":"Kernel team discussions ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Content-Type":"text/plain; charset=\"utf-8\"","Content-Transfer-Encoding":"base64","Errors-To":"kernel-team-bounces@lists.ubuntu.com","Sender":"\"kernel-team\" "}},{"id":3680917,"web_url":"http://patchwork.ozlabs.org/comment/3680917/","msgid":"<87340mss9q.fsf@gmail.com>","list_archive_url":null,"date":"2026-04-22T19:34:57","subject":"APPLIED: [SRU][Q][PATCH 0/1] Revert \"iommu: disable SVA when\n CONFIG_X86 is set\"","submitter":{"id":89305,"url":"http://patchwork.ozlabs.org/api/people/89305/","name":"Mehmet Basaran","email":"mehmet.basaran@canonical.com"},"content":"Applied to questing:linux master-next branch. Thanks.\nMehmet Basaran writes:\n\n> BugLink: https://bugs.launchpad.net/bugs/2149766\n>\n> [Impact]\n> \n> The issue has been brought to our attention when questing (6.17)\n> kernels were unable to load amd_xdna drivers. However, this commit,\n> in addition to NPUs, also affects PCIe cards which make use of\n> unified memory (GPUs, Accelerators, NICs). With this commit, PCIe\n> devices will revert to using legacy method (pinning) instead of\n> unified memory. As a result,\n> - arguably it will be less secure,\n> - there can be performance drops.\n>\n> Currently, this commit is part of an 8 commit patch series:\n> \"Fix stale IOTLB entries for kernel address space\", v7.\n> [PATCH v7 1/8] iommu: Disable SVA when CONFIG_X86 is set\n> [PATCH v7 2/8] mm: Add a ptdesc flag to mark kernel page tables\n> [PATCH v7 3/8] mm: Actually mark kernel page table pages\n> [PATCH v7 4/8] x86/mm: Use 'ptdesc' when freeing PMD pages\n> [PATCH v7 5/8] mm: Introduce pure page table freeing function\n> [PATCH v7 6/8] x86/mm: Use pagetable_free()\n> [PATCH v7 7/8] mm: Introduce deferred freeing for kernel page tables\n> [PATCH v7 8/8] iommu/sva: Invalidate stale IOTLB entries for kernel address space\n>\n> where \"iommu: disable SVA when CONFIG_X86 is set\" is undone by\n> the 8th commit. We only have this commit from the whole patchset.\n> Ideally we should have the whole patchset applied.\n>\n> [Fix]\n>\n> This commit fixes the following issue which is old,\n> 26b25a2b98e4 (\"iommu: Bind process address spaces to devices\")\n> and we applied this commit recently. So, reverting this commit\n> won't be introducing regressions. Affected kernel versions are:\n> - 6.8 due to the reasons above.\n> - 6.17 due to both the reasons above and the amd_xdna issue.\n>\n> [Test Plan]\n>\n> Our regression test suite doesn't catch this issue. However,\n> we will run it again to see it doesn't cause anything else.\n>\n> [Where problems could occur]\n>\n> Reverted commit is a fix for a security vulnerability related to\n> IOMMU Shared Virtual Addressing (SVA). In an SVA context, an \n> IOMMU can cache kernel page table entries. When a kernel page \n> table page is freed and reallocated for another purpose, the \n> IOMMU might still hold stale, incorrect entries. This can be \n> exploited to cause a use-after-free or write-after-free condition,\n> potentially leading to privilege escalation or data corruption.\n>\n> Mehmet Basaran (1):\n> Revert \"iommu: disable SVA when CONFIG_X86 is set\"\n>\n> drivers/iommu/iommu-sva.c | 3 ---\n> 1 file changed, 3 deletions(-)\n>\n> -- \n> 2.43.0","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=fail reason=\"signature verification failed\" (4096-bit key;\n unprotected) header.d=canonical.com header.i=@canonical.com\n header.a=rsa-sha256 header.s=20251003 header.b=q+rB2Bvo;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=lists.ubuntu.com\n (client-ip=185.125.189.65; helo=lists.ubuntu.com;\n envelope-from=kernel-team-bounces@lists.ubuntu.com;\n receiver=patchwork.ozlabs.org)"],"Received":["from lists.ubuntu.com (lists.ubuntu.com [185.125.189.65])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g18ZZ4F0zz1y2d\n\tfor ; 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