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[tip: x86/urgent] x86/CPU/AMD: Ignore invalid reset reason value

by tip-bot2 for Yazen Ghannam

The following commit has been merged into the x86/urgent branch of tip: Commit-ID: e9576e078220c50ace9e9087355423de23e25fa5 Gitweb: https://git.kernel.org/tip/e9576e078220c50ace9e9087355423de23e25fa5 Author: Yazen Ghannam <yazen.ghannam(a)amd.com> AuthorDate: Mon, 21 Jul 2025 18:11:54 Committer: Borislav Petkov (AMD) <bp(a)alien8.de> CommitterDate: Mon, 18 Aug 2025 16:36:59 +02:00 x86/CPU/AMD: Ignore invalid reset reason value The reset reason value may be "all bits set", e.g. 0xFFFFFFFF. This is a commonly used error response from hardware. This may occur due to a real hardware issue or when running in a VM. The user will see all reset reasons reported in this case. Check for an error response value and return early to avoid decoding invalid data. Also, adjust the data variable type to match the hardware register size. Fixes: ab8131028710 ("x86/CPU/AMD: Print the reason for the last reset") Reported-by: Libing He <libhe(a)redhat.com> Signed-off-by: Yazen Ghannam <yazen.ghannam(a)amd.com> Signed-off-by: Borislav Petkov (AMD) <bp(a)alien8.de> Reviewed-by: Mario Limonciello <mario.limonciello(a)amd.com> Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/20250721181155.3536023-1-yazen.ghannam@amd.com --- arch/x86/kernel/cpu/amd.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index a5ece6e..a6f88ca 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -1326,8 +1326,8 @@ static const char * const s5_reset_reason_txt[] = { static __init int print_s5_reset_status_mmio(void) { - unsigned long value; void __iomem *addr; + u32 value; int i; if (!cpu_feature_enabled(X86_FEATURE_ZEN)) @@ -1340,12 +1340,16 @@ static __init int print_s5_reset_status_mmio(void) value = ioread32(addr); iounmap(addr); + /* Value with "all bits set" is an error response and should be ignored. */ + if (value == U32_MAX) + return 0; + for (i = 0; i < ARRAY_SIZE(s5_reset_reason_txt); i++) { if (!(value & BIT(i))) continue; if (s5_reset_reason_txt[i]) { - pr_info("x86/amd: Previous system reset reason [0x%08lx]: %s\n", + pr_info("x86/amd: Previous system reset reason [0x%08x]: %s\n", value, s5_reset_reason_txt[i]); } }

3 months

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[REGRESSION] stable-rc/linux-5.4.y: (build) ‘CPUFREQ_NEED_UPDATE_LIMITS’ undeclared here (not in a function) i...

by KernelCI bot

Hello, New build issue found on stable-rc/linux-5.4.y: --- ‘CPUFREQ_NEED_UPDATE_LIMITS’ undeclared here (not in a function) in drivers/cpufreq/cppc_cpufreq.o (drivers/cpufreq/cppc_cpufreq.c) [logspec:kbuild,kbuild.compiler.error] --- - dashboard: https://d.kernelci.org/i/maestro:dc41002c36bbf28f576cb4cf62779067892fb9db - giturl: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git - commit HEAD: a6319f2fe27b8fefe40757d3797cfca30d43ce3c Log excerpt: ===================================================== drivers/cpufreq/cppc_cpufreq.c:410:40: error: ‘CPUFREQ_NEED_UPDATE_LIMITS’ undeclared here (not in a function) 410 | .flags = CPUFREQ_CONST_LOOPS | CPUFREQ_NEED_UPDATE_LIMITS, | ^~~~~~~~~~~~~~~~~~~~~~~~~~ ===================================================== # Builds where the incident occurred: ## defconfig+arm64-chromebook+kselftest on (arm64): - compiler: gcc-12 - dashboard: https://d.kernelci.org/build/maestro:68a3251d233e484a3f9e9e33 ## defconfig+lab-setup+arm64-chromebook+CONFIG_MODULE_COMPRESS=n+CONFIG_MODULE_COMPRESS_NONE=y on (arm64): - compiler: gcc-12 - dashboard: https://d.kernelci.org/build/maestro:68a324d8233e484a3f9e9df2 ## defconfig+lab-setup+kselftest on (arm64): - compiler: gcc-12 - dashboard: https://d.kernelci.org/build/maestro:68a32513233e484a3f9e9e2a #kernelci issue maestro:dc41002c36bbf28f576cb4cf62779067892fb9db Reported-by: kernelci.org bot <bot(a)kernelci.org> -- This is an experimental report format. Please send feedback in! Talk to us at kernelci(a)lists.linux.dev Made with love by the KernelCI team - https://kernelci.org

3 months

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[REGRESSION] stable-rc/linux-5.4.y: (build) use of undeclared identifier 'CPUFREQ_NEED_UPDATE_LIMITS' in drive...

by KernelCI bot

Hello, New build issue found on stable-rc/linux-5.4.y: --- use of undeclared identifier 'CPUFREQ_NEED_UPDATE_LIMITS' in drivers/cpufreq/cppc_cpufreq.o (drivers/cpufreq/cppc_cpufreq.c) [logspec:kbuild,kbuild.compiler.error] --- - dashboard: https://d.kernelci.org/i/maestro:b9c80192e71f04dd69fa1038881cb02b2c46b045 - giturl: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git - commit HEAD: a6319f2fe27b8fefe40757d3797cfca30d43ce3c Log excerpt: ===================================================== drivers/cpufreq/cppc_cpufreq.c:410:33: error: use of undeclared identifier 'CPUFREQ_NEED_UPDATE_LIMITS' 410 | .flags = CPUFREQ_CONST_LOOPS | CPUFREQ_NEED_UPDATE_LIMITS, | ^ 1 error generated. ===================================================== # Builds where the incident occurred: ## defconfig+arm64-chromebook+kselftest on (arm64): - compiler: clang-17 - dashboard: https://d.kernelci.org/build/maestro:68a324ee233e484a3f9e9e07 #kernelci issue maestro:b9c80192e71f04dd69fa1038881cb02b2c46b045 Reported-by: kernelci.org bot <bot(a)kernelci.org> -- This is an experimental report format. Please send feedback in! Talk to us at kernelci(a)lists.linux.dev Made with love by the KernelCI team - https://kernelci.org

3 months

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[REGRESSION] IPv6 RA default router advertisement fails after kernel 6.12.42 updates

by 喵公子

Hi, While testing Linux kernel 6.12.42 on OpenWrt, we observed a regression in IPv6 Router Advertisement (RA) handling for the default router. Affected commits The following commits appear related and may have introduced the issue: ipv6: fix possible infinite loop in fib6_info_uses_dev()： https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=… ipv6: prevent infinite loop in rt6_nlmsg_size()： https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=… ipv6: annotate data-races around rt->fib6_nsiblings： https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=… Problem description： In Linux kernel 6.12.42, IPv6 FIB multipath and concurrent access handling was made stricter (READ_ONCE / WRITE_ONCE + RCU retry). The RA “Automatic” mode relies on checking whether a local default route exists. With the stricter FIB handling, this check can fail in multipath scenarios. As a result, RA does not advertise a default route, and IPv6 clients on LAN fail to receive the default gateway. Steps to reproduce Run OpenWrt with kernel 6.12.42 on a router with br-lan bridge. Configure IPv6 RA in Automatic default router mode. Observe that no default route is advertised to clients (though prefixes may still be delivered). Expected behavior Router Advertisement should continue to advertise the default route as in kernel 6.12.41 and earlier. Client IPv6 connectivity should not break. Actual behavior RA fails to advertise a default route in Automatic mode. Clients do not install a default IPv6 route → connectivity fails. Temporary workaround Change RA default router mode from Automatic → Always / Use available prefixes in OpenWrt. This bypasses the dependency on local default route check and restores correct RA behavior. Additional notes This appears to be an unintended side effect of the stricter FIB handling changes introduced in 6.12.42. Please advise if this has already been reported or if I should prepare a minimal reproducer outside OpenWrt. Thanks, [GitHub: mgz0227]

3 months

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[PATCH v2 0/2] media: pci: Fix invalid access to file *

by Jacopo Mondi

Since commits 7b9eb53e8591 ("media: cx18: Access v4l2_fh from file") 9ba9d11544f9 ("media: ivtv: Access v4l2_fh from file") All the ioctl handlers access their private data structures from file * The ivtv and cx18 drivers call the ioctl handlers from their DVB layer without a valid file *, causing invalid memory access. The issue has been reported by smatch in "[bug report] media: cx18: Access v4l2_fh from file" Fix this by providing wrappers for the ioctl handlers to be used by the DVB layer that do not require a valid file *. Signed-off-by: Jacopo Mondi <jacopo.mondi(a)ideasonboard.com> --- Changes in v2: - Add Cc: stable(a)vger.kernel.org per-patch --- Jacopo Mondi (2): media: cx18: Fix invalid access to file * media: ivtv: Fix invalid access to file * drivers/media/pci/cx18/cx18-driver.c | 6 +++--- drivers/media/pci/cx18/cx18-ioctl.c | 26 ++++++++++++++++++++------ drivers/media/pci/cx18/cx18-ioctl.h | 8 +++++--- drivers/media/pci/ivtv/ivtv-driver.c | 4 ++-- drivers/media/pci/ivtv/ivtv-ioctl.c | 22 +++++++++++++++++----- drivers/media/pci/ivtv/ivtv-ioctl.h | 6 ++++-- 6 files changed, 51 insertions(+), 21 deletions(-) --- base-commit: a75b8d198c55e9eb5feb6f6e155496305caba2dc change-id: 20250818-cx18-v4l2-fh-7eaa6199fdde Best regards, -- Jacopo Mondi <jacopo.mondi(a)ideasonboard.com>

3 months

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[PATCH 0/2] media: pci: Fix invalid access to file *

by Jacopo Mondi

Since commits 7b9eb53e8591 ("media: cx18: Access v4l2_fh from file") 9ba9d11544f9 ("media: ivtv: Access v4l2_fh from file") All the ioctl handlers access their private data structures from file * The ivtv and cx18 drivers call the ioctl handlers from their DVB layer without a valid file *, causing invalid memory access. The issue has been reported by smatch in "[bug report] media: cx18: Access v4l2_fh from file" Fix this by providing wrappers for the ioctl handlers to be used by the DVB layer that do not require a valid file *. Signed-off-by: Jacopo Mondi <jacopo.mondi(a)ideasonboard.com> --- Jacopo Mondi (2): media: cx18: Fix invalid access to file * media: ivtv: Fix invalid access to file * drivers/media/pci/cx18/cx18-driver.c | 6 +++--- drivers/media/pci/cx18/cx18-ioctl.c | 26 ++++++++++++++++++++------ drivers/media/pci/cx18/cx18-ioctl.h | 8 +++++--- drivers/media/pci/ivtv/ivtv-driver.c | 4 ++-- drivers/media/pci/ivtv/ivtv-ioctl.c | 22 +++++++++++++++++----- drivers/media/pci/ivtv/ivtv-ioctl.h | 6 ++++-- 6 files changed, 51 insertions(+), 21 deletions(-) --- base-commit: a75b8d198c55e9eb5feb6f6e155496305caba2dc change-id: 20250818-cx18-v4l2-fh-7eaa6199fdde Best regards, -- Jacopo Mondi <jacopo.mondi(a)ideasonboard.com>

3 months

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[PATCH RESEND v2] proc: fix missing pde_set_flags() for net proc files

by wangzijie

To avoid potential UAF issues during module removal races, we use pde_set_flags() to save proc_ops flags in PDE itself before proc_register(), and then use pde_has_proc_*() helpers instead of directly dereferencing pde->proc_ops->*. However, the pde_set_flags() call was missing when creating net related proc files. This omission caused incorrect behavior which FMODE_LSEEK was being cleared inappropriately in proc_reg_open() for net proc files. Lars reported it in this link[1]. Fix this by ensuring pde_set_flags() is called when register proc entry, and add NULL check for proc_ops in pde_set_flags(). [1]: https://lore.kernel.org/all/20250815195616.64497967@chagall.paradoxon.rec/ Fixes: ff7ec8dc1b64 ("proc: use the same treatment to check proc_lseek as ones for proc_read_iter et.al) Cc: stable(a)vger.kernel.org Reported-by: Lars Wendler <polynomial-c(a)gmx.de> Signed-off-by: wangzijie <wangzijie1(a)honor.com> --- fs/proc/generic.c | 36 +++++++++++++++++++----------------- 1 file changed, 19 insertions(+), 17 deletions(-) diff --git a/fs/proc/generic.c b/fs/proc/generic.c index 76e800e38..003031839 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -367,6 +367,23 @@ static const struct inode_operations proc_dir_inode_operations = { .setattr = proc_notify_change, }; +static void pde_set_flags(struct proc_dir_entry *pde) +{ + if (!pde->proc_ops) + return; + + if (pde->proc_ops->proc_flags & PROC_ENTRY_PERMANENT) + pde->flags |= PROC_ENTRY_PERMANENT; + if (pde->proc_ops->proc_read_iter) + pde->flags |= PROC_ENTRY_proc_read_iter; +#ifdef CONFIG_COMPAT + if (pde->proc_ops->proc_compat_ioctl) + pde->flags |= PROC_ENTRY_proc_compat_ioctl; +#endif + if (pde->proc_ops->proc_lseek) + pde->flags |= PROC_ENTRY_proc_lseek; +} + /* returns the registered entry, or frees dp and returns NULL on failure */ struct proc_dir_entry *proc_register(struct proc_dir_entry *dir, struct proc_dir_entry *dp) @@ -374,6 +391,8 @@ struct proc_dir_entry *proc_register(struct proc_dir_entry *dir, if (proc_alloc_inum(&dp->low_ino)) goto out_free_entry; + pde_set_flags(dp); + write_lock(&proc_subdir_lock); dp->parent = dir; if (pde_subdir_insert(dir, dp) == false) { @@ -561,20 +580,6 @@ struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode, return p; } -static void pde_set_flags(struct proc_dir_entry *pde) -{ - if (pde->proc_ops->proc_flags & PROC_ENTRY_PERMANENT) - pde->flags |= PROC_ENTRY_PERMANENT; - if (pde->proc_ops->proc_read_iter) - pde->flags |= PROC_ENTRY_proc_read_iter; -#ifdef CONFIG_COMPAT - if (pde->proc_ops->proc_compat_ioctl) - pde->flags |= PROC_ENTRY_proc_compat_ioctl; -#endif - if (pde->proc_ops->proc_lseek) - pde->flags |= PROC_ENTRY_proc_lseek; -} - struct proc_dir_entry *proc_create_data(const char *name, umode_t mode, struct proc_dir_entry *parent, const struct proc_ops *proc_ops, void *data) @@ -585,7 +590,6 @@ struct proc_dir_entry *proc_create_data(const char *name, umode_t mode, if (!p) return NULL; p->proc_ops = proc_ops; - pde_set_flags(p); return proc_register(parent, p); } EXPORT_SYMBOL(proc_create_data); @@ -636,7 +640,6 @@ struct proc_dir_entry *proc_create_seq_private(const char *name, umode_t mode, p->proc_ops = &proc_seq_ops; p->seq_ops = ops; p->state_size = state_size; - pde_set_flags(p); return proc_register(parent, p); } EXPORT_SYMBOL(proc_create_seq_private); @@ -667,7 +670,6 @@ struct proc_dir_entry *proc_create_single_data(const char *name, umode_t mode, return NULL; p->proc_ops = &proc_single_ops; p->single_show = show; - pde_set_flags(p); return proc_register(parent, p); } EXPORT_SYMBOL(proc_create_single_data); -- 2.25.1

3 months

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FAILED: patch "[PATCH] iommu/vt-d: Make iotlb_sync_map a static property of" failed to apply to 6.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.15.y git checkout FETCH_HEAD git cherry-pick -x cee686775f9cd4eae31f3c1f7ec24b2048082667 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081823-muzzle-defiant-69ef@gregkh' --subject-prefix 'PATCH 6.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From cee686775f9cd4eae31f3c1f7ec24b2048082667 Mon Sep 17 00:00:00 2001 From: Lu Baolu <baolu.lu(a)linux.intel.com> Date: Mon, 21 Jul 2025 13:16:57 +0800 Subject: [PATCH] iommu/vt-d: Make iotlb_sync_map a static property of dmar_domain Commit 12724ce3fe1a ("iommu/vt-d: Optimize iotlb_sync_map for non-caching/non-RWBF modes") dynamically set iotlb_sync_map. This causes synchronization issues due to lack of locking on map and attach paths, racing iommufd userspace operations. Invalidation changes must precede device attachment to ensure all flushes complete before hardware walks page tables, preventing coherence issues. Make domain->iotlb_sync_map static, set once during domain allocation. If an IOMMU requires iotlb_sync_map but the domain lacks it, attach is rejected. This won't reduce domain sharing: RWBF and shadowing page table caching are legacy uses with legacy hardware. Mixed configs (some IOMMUs in caching mode, others not) are unlikely in real-world scenarios. Fixes: 12724ce3fe1a ("iommu/vt-d: Optimize iotlb_sync_map for non-caching/non-RWBF modes") Suggested-by: Jason Gunthorpe <jgg(a)nvidia.com> Signed-off-by: Lu Baolu <baolu.lu(a)linux.intel.com> Link: https://lore.kernel.org/r/20250721051657.1695788-1-baolu.lu@linux.intel.com Signed-off-by: Will Deacon <will(a)kernel.org> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 3e774e3bb735..d1791b50f791 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -57,6 +57,8 @@ static void __init check_tylersburg_isoch(void); static int rwbf_quirk; +#define rwbf_required(iommu) (rwbf_quirk || cap_rwbf((iommu)->cap)) + /* * set to 1 to panic kernel if can't successfully enable VT-d * (used when kernel is launched w/ TXT) @@ -1780,18 +1782,6 @@ static int domain_setup_first_level(struct intel_iommu *iommu, __pa(pgd), flags, old); } -static bool domain_need_iotlb_sync_map(struct dmar_domain *domain, - struct intel_iommu *iommu) -{ - if (cap_caching_mode(iommu->cap) && intel_domain_is_ss_paging(domain)) - return true; - - if (rwbf_quirk || cap_rwbf(iommu->cap)) - return true; - - return false; -} - static int dmar_domain_attach_device(struct dmar_domain *domain, struct device *dev) { @@ -1831,8 +1821,6 @@ static int dmar_domain_attach_device(struct dmar_domain *domain, if (ret) goto out_block_translation; - domain->iotlb_sync_map |= domain_need_iotlb_sync_map(domain, iommu); - return 0; out_block_translation: @@ -3352,6 +3340,14 @@ intel_iommu_domain_alloc_first_stage(struct device *dev, return ERR_CAST(dmar_domain); dmar_domain->domain.ops = &intel_fs_paging_domain_ops; + /* + * iotlb sync for map is only needed for legacy implementations that + * explicitly require flushing internal write buffers to ensure memory + * coherence. + */ + if (rwbf_required(iommu)) + dmar_domain->iotlb_sync_map = true; + return &dmar_domain->domain; } @@ -3386,6 +3382,14 @@ intel_iommu_domain_alloc_second_stage(struct device *dev, if (flags & IOMMU_HWPT_ALLOC_DIRTY_TRACKING) dmar_domain->domain.dirty_ops = &intel_dirty_ops; + /* + * Besides the internal write buffer flush, the caching mode used for + * legacy nested translation (which utilizes shadowing page tables) + * also requires iotlb sync on map. + */ + if (rwbf_required(iommu) || cap_caching_mode(iommu->cap)) + dmar_domain->iotlb_sync_map = true; + return &dmar_domain->domain; } @@ -3446,6 +3450,11 @@ static int paging_domain_compatible_first_stage(struct dmar_domain *dmar_domain, if (!cap_fl1gp_support(iommu->cap) && (dmar_domain->domain.pgsize_bitmap & SZ_1G)) return -EINVAL; + + /* iotlb sync on map requirement */ + if ((rwbf_required(iommu)) && !dmar_domain->iotlb_sync_map) + return -EINVAL; + return 0; } @@ -3469,6 +3478,12 @@ paging_domain_compatible_second_stage(struct dmar_domain *dmar_domain, return -EINVAL; if (!(sslps & BIT(1)) && (dmar_domain->domain.pgsize_bitmap & SZ_1G)) return -EINVAL; + + /* iotlb sync on map requirement */ + if ((rwbf_required(iommu) || cap_caching_mode(iommu->cap)) && + !dmar_domain->iotlb_sync_map) + return -EINVAL; + return 0; }

3 months

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FAILED: patch "[PATCH] iommu/vt-d: Make iotlb_sync_map a static property of" failed to apply to 6.12-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x cee686775f9cd4eae31f3c1f7ec24b2048082667 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081823-waking-baritone-c887@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From cee686775f9cd4eae31f3c1f7ec24b2048082667 Mon Sep 17 00:00:00 2001 From: Lu Baolu <baolu.lu(a)linux.intel.com> Date: Mon, 21 Jul 2025 13:16:57 +0800 Subject: [PATCH] iommu/vt-d: Make iotlb_sync_map a static property of dmar_domain Commit 12724ce3fe1a ("iommu/vt-d: Optimize iotlb_sync_map for non-caching/non-RWBF modes") dynamically set iotlb_sync_map. This causes synchronization issues due to lack of locking on map and attach paths, racing iommufd userspace operations. Invalidation changes must precede device attachment to ensure all flushes complete before hardware walks page tables, preventing coherence issues. Make domain->iotlb_sync_map static, set once during domain allocation. If an IOMMU requires iotlb_sync_map but the domain lacks it, attach is rejected. This won't reduce domain sharing: RWBF and shadowing page table caching are legacy uses with legacy hardware. Mixed configs (some IOMMUs in caching mode, others not) are unlikely in real-world scenarios. Fixes: 12724ce3fe1a ("iommu/vt-d: Optimize iotlb_sync_map for non-caching/non-RWBF modes") Suggested-by: Jason Gunthorpe <jgg(a)nvidia.com> Signed-off-by: Lu Baolu <baolu.lu(a)linux.intel.com> Link: https://lore.kernel.org/r/20250721051657.1695788-1-baolu.lu@linux.intel.com Signed-off-by: Will Deacon <will(a)kernel.org> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 3e774e3bb735..d1791b50f791 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -57,6 +57,8 @@ static void __init check_tylersburg_isoch(void); static int rwbf_quirk; +#define rwbf_required(iommu) (rwbf_quirk || cap_rwbf((iommu)->cap)) + /* * set to 1 to panic kernel if can't successfully enable VT-d * (used when kernel is launched w/ TXT) @@ -1780,18 +1782,6 @@ static int domain_setup_first_level(struct intel_iommu *iommu, __pa(pgd), flags, old); } -static bool domain_need_iotlb_sync_map(struct dmar_domain *domain, - struct intel_iommu *iommu) -{ - if (cap_caching_mode(iommu->cap) && intel_domain_is_ss_paging(domain)) - return true; - - if (rwbf_quirk || cap_rwbf(iommu->cap)) - return true; - - return false; -} - static int dmar_domain_attach_device(struct dmar_domain *domain, struct device *dev) { @@ -1831,8 +1821,6 @@ static int dmar_domain_attach_device(struct dmar_domain *domain, if (ret) goto out_block_translation; - domain->iotlb_sync_map |= domain_need_iotlb_sync_map(domain, iommu); - return 0; out_block_translation: @@ -3352,6 +3340,14 @@ intel_iommu_domain_alloc_first_stage(struct device *dev, return ERR_CAST(dmar_domain); dmar_domain->domain.ops = &intel_fs_paging_domain_ops; + /* + * iotlb sync for map is only needed for legacy implementations that + * explicitly require flushing internal write buffers to ensure memory + * coherence. + */ + if (rwbf_required(iommu)) + dmar_domain->iotlb_sync_map = true; + return &dmar_domain->domain; } @@ -3386,6 +3382,14 @@ intel_iommu_domain_alloc_second_stage(struct device *dev, if (flags & IOMMU_HWPT_ALLOC_DIRTY_TRACKING) dmar_domain->domain.dirty_ops = &intel_dirty_ops; + /* + * Besides the internal write buffer flush, the caching mode used for + * legacy nested translation (which utilizes shadowing page tables) + * also requires iotlb sync on map. + */ + if (rwbf_required(iommu) || cap_caching_mode(iommu->cap)) + dmar_domain->iotlb_sync_map = true; + return &dmar_domain->domain; } @@ -3446,6 +3450,11 @@ static int paging_domain_compatible_first_stage(struct dmar_domain *dmar_domain, if (!cap_fl1gp_support(iommu->cap) && (dmar_domain->domain.pgsize_bitmap & SZ_1G)) return -EINVAL; + + /* iotlb sync on map requirement */ + if ((rwbf_required(iommu)) && !dmar_domain->iotlb_sync_map) + return -EINVAL; + return 0; } @@ -3469,6 +3478,12 @@ paging_domain_compatible_second_stage(struct dmar_domain *dmar_domain, return -EINVAL; if (!(sslps & BIT(1)) && (dmar_domain->domain.pgsize_bitmap & SZ_1G)) return -EINVAL; + + /* iotlb sync on map requirement */ + if ((rwbf_required(iommu) || cap_caching_mode(iommu->cap)) && + !dmar_domain->iotlb_sync_map) + return -EINVAL; + return 0; }

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FAILED: patch "[PATCH] iommu/vt-d: Make iotlb_sync_map a static property of" failed to apply to 6.16-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.16-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.16.y git checkout FETCH_HEAD git cherry-pick -x cee686775f9cd4eae31f3c1f7ec24b2048082667 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025081822-quill-yeah-a207@gregkh' --subject-prefix 'PATCH 6.16.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From cee686775f9cd4eae31f3c1f7ec24b2048082667 Mon Sep 17 00:00:00 2001 From: Lu Baolu <baolu.lu(a)linux.intel.com> Date: Mon, 21 Jul 2025 13:16:57 +0800 Subject: [PATCH] iommu/vt-d: Make iotlb_sync_map a static property of dmar_domain Commit 12724ce3fe1a ("iommu/vt-d: Optimize iotlb_sync_map for non-caching/non-RWBF modes") dynamically set iotlb_sync_map. This causes synchronization issues due to lack of locking on map and attach paths, racing iommufd userspace operations. Invalidation changes must precede device attachment to ensure all flushes complete before hardware walks page tables, preventing coherence issues. Make domain->iotlb_sync_map static, set once during domain allocation. If an IOMMU requires iotlb_sync_map but the domain lacks it, attach is rejected. This won't reduce domain sharing: RWBF and shadowing page table caching are legacy uses with legacy hardware. Mixed configs (some IOMMUs in caching mode, others not) are unlikely in real-world scenarios. Fixes: 12724ce3fe1a ("iommu/vt-d: Optimize iotlb_sync_map for non-caching/non-RWBF modes") Suggested-by: Jason Gunthorpe <jgg(a)nvidia.com> Signed-off-by: Lu Baolu <baolu.lu(a)linux.intel.com> Link: https://lore.kernel.org/r/20250721051657.1695788-1-baolu.lu@linux.intel.com Signed-off-by: Will Deacon <will(a)kernel.org> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 3e774e3bb735..d1791b50f791 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -57,6 +57,8 @@ static void __init check_tylersburg_isoch(void); static int rwbf_quirk; +#define rwbf_required(iommu) (rwbf_quirk || cap_rwbf((iommu)->cap)) + /* * set to 1 to panic kernel if can't successfully enable VT-d * (used when kernel is launched w/ TXT) @@ -1780,18 +1782,6 @@ static int domain_setup_first_level(struct intel_iommu *iommu, __pa(pgd), flags, old); } -static bool domain_need_iotlb_sync_map(struct dmar_domain *domain, - struct intel_iommu *iommu) -{ - if (cap_caching_mode(iommu->cap) && intel_domain_is_ss_paging(domain)) - return true; - - if (rwbf_quirk || cap_rwbf(iommu->cap)) - return true; - - return false; -} - static int dmar_domain_attach_device(struct dmar_domain *domain, struct device *dev) { @@ -1831,8 +1821,6 @@ static int dmar_domain_attach_device(struct dmar_domain *domain, if (ret) goto out_block_translation; - domain->iotlb_sync_map |= domain_need_iotlb_sync_map(domain, iommu); - return 0; out_block_translation: @@ -3352,6 +3340,14 @@ intel_iommu_domain_alloc_first_stage(struct device *dev, return ERR_CAST(dmar_domain); dmar_domain->domain.ops = &intel_fs_paging_domain_ops; + /* + * iotlb sync for map is only needed for legacy implementations that + * explicitly require flushing internal write buffers to ensure memory + * coherence. + */ + if (rwbf_required(iommu)) + dmar_domain->iotlb_sync_map = true; + return &dmar_domain->domain; } @@ -3386,6 +3382,14 @@ intel_iommu_domain_alloc_second_stage(struct device *dev, if (flags & IOMMU_HWPT_ALLOC_DIRTY_TRACKING) dmar_domain->domain.dirty_ops = &intel_dirty_ops; + /* + * Besides the internal write buffer flush, the caching mode used for + * legacy nested translation (which utilizes shadowing page tables) + * also requires iotlb sync on map. + */ + if (rwbf_required(iommu) || cap_caching_mode(iommu->cap)) + dmar_domain->iotlb_sync_map = true; + return &dmar_domain->domain; } @@ -3446,6 +3450,11 @@ static int paging_domain_compatible_first_stage(struct dmar_domain *dmar_domain, if (!cap_fl1gp_support(iommu->cap) && (dmar_domain->domain.pgsize_bitmap & SZ_1G)) return -EINVAL; + + /* iotlb sync on map requirement */ + if ((rwbf_required(iommu)) && !dmar_domain->iotlb_sync_map) + return -EINVAL; + return 0; } @@ -3469,6 +3478,12 @@ paging_domain_compatible_second_stage(struct dmar_domain *dmar_domain, return -EINVAL; if (!(sslps & BIT(1)) && (dmar_domain->domain.pgsize_bitmap & SZ_1G)) return -EINVAL; + + /* iotlb sync on map requirement */ + if ((rwbf_required(iommu) || cap_caching_mode(iommu->cap)) && + !dmar_domain->iotlb_sync_map) + return -EINVAL; + return 0; }

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