From 526606b0a1998b0791b42c199d53550c3ba724b5 Mon Sep 17 00:00:00 2001 From: Vasant Hegde Date: Thu, 30 May 2024 08:48:01 +0000 Subject: [PATCH] iommu/amd: Fix Invalid wait context issue With commit c4cb23111103 ("iommu/amd: Add support for enable/disable IOPF") we are hitting below issue. This happens because in IOPF enablement path it holds spin lock with irq disable and then tries to take mutex lock. dmesg: ----- [ 0.938739] ============================= [ 0.938740] [ BUG: Invalid wait context ] [ 0.938742] 6.10.0-rc1+ #1 Not tainted [ 0.938745] ----------------------------- [ 0.938746] swapper/0/1 is trying to lock: [ 0.938748] ffffffff8c9f01d8 (&port_lock_key){....}-{3:3}, at: serial8250_console_write+0x78/0x4a0 [ 0.938767] other info that might help us debug this: [ 0.938768] context-{5:5} [ 0.938769] 7 locks held by swapper/0/1: [ 0.938772] #0: ffff888101a91310 (&group->mutex){+.+.}-{4:4}, at: bus_iommu_probe+0x70/0x160 [ 0.938790] #1: ffff888101d1f1b8 (&domain->lock){....}-{3:3}, at: amd_iommu_attach_device+0xa5/0x700 [ 0.938799] #2: ffff888101cc3d18 (&dev_data->lock){....}-{3:3}, at: amd_iommu_attach_device+0xc5/0x700 [ 0.938806] #3: ffff888100052830 (&iommu->lock){....}-{2:2}, at: amd_iommu_iopf_add_device+0x3f/0xa0 [ 0.938813] #4: ffffffff8945a340 (console_lock){+.+.}-{0:0}, at: _printk+0x48/0x50 [ 0.938822] #5: ffffffff8945a390 (console_srcu){....}-{0:0}, at: console_flush_all+0x58/0x4e0 [ 0.938867] #6: ffffffff82459f80 (console_owner){....}-{0:0}, at: console_flush_all+0x1f0/0x4e0 [ 0.938872] stack backtrace: [ 0.938874] CPU: 2 PID: 1 Comm: swapper/0 Not tainted 6.10.0-rc1+ #1 [ 0.938877] Hardware name: HP HP EliteBook 745 G3/807E, BIOS N73 Ver. 01.39 04/16/2019 Fix above issue by re-arranging code in attach device path: - move device PASID/IOPF enablement outside lock in AMD IOMMU driver. This is safe as core layer holds group->mutex lock before calling iommu_ops->attach_dev. Reported-by: Borislav Petkov Reported-by: Mikhail Gavrilov Reported-by: Chris Bainbridge Fixes: c4cb23111103 ("iommu/amd: Add support for enable/disable IOPF") Tested-by: Borislav Petkov Tested-by: Chris Bainbridge Tested-by: Mikhail Gavrilov Signed-off-by: Vasant Hegde Link: https://lore.kernel.org/r/20240530084801.10758-1-vasant.hegde@amd.com Signed-off-by: Joerg Roedel --- drivers/iommu/amd/iommu.c | 48 +++++++++++++++++++-------------------- drivers/iommu/amd/ppr.c | 22 ++++-------------- 2 files changed, 28 insertions(+), 42 deletions(-) diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c index 52d83730a22ad4..c2703599bb1668 100644 --- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -2032,7 +2032,6 @@ static int do_attach(struct iommu_dev_data *dev_data, struct protection_domain *domain) { struct amd_iommu *iommu = get_amd_iommu_from_dev_data(dev_data); - struct pci_dev *pdev; int ret = 0; /* Update data structures */ @@ -2047,30 +2046,13 @@ static int do_attach(struct iommu_dev_data *dev_data, domain->dev_iommu[iommu->index] += 1; domain->dev_cnt += 1; - pdev = dev_is_pci(dev_data->dev) ? to_pci_dev(dev_data->dev) : NULL; + /* Setup GCR3 table */ if (pdom_is_sva_capable(domain)) { ret = init_gcr3_table(dev_data, domain); if (ret) return ret; - - if (pdev) { - pdev_enable_caps(pdev); - - /* - * Device can continue to function even if IOPF - * enablement failed. Hence in error path just - * disable device PRI support. - */ - if (amd_iommu_iopf_add_device(iommu, dev_data)) - pdev_disable_cap_pri(pdev); - } - } else if (pdev) { - pdev_enable_cap_ats(pdev); } - /* Update device table */ - amd_iommu_dev_update_dte(dev_data, true); - return ret; } @@ -2163,6 +2145,11 @@ static void detach_device(struct device *dev) do_detach(dev_data); +out: + spin_unlock(&dev_data->lock); + + spin_unlock_irqrestore(&domain->lock, flags); + /* Remove IOPF handler */ if (ppr) amd_iommu_iopf_remove_device(iommu, dev_data); @@ -2170,10 +2157,6 @@ static void detach_device(struct device *dev) if (dev_is_pci(dev)) pdev_disable_caps(to_pci_dev(dev)); -out: - spin_unlock(&dev_data->lock); - - spin_unlock_irqrestore(&domain->lock, flags); } static struct iommu_device *amd_iommu_probe_device(struct device *dev) @@ -2485,6 +2468,7 @@ static int amd_iommu_attach_device(struct iommu_domain *dom, struct iommu_dev_data *dev_data = dev_iommu_priv_get(dev); struct protection_domain *domain = to_pdomain(dom); struct amd_iommu *iommu = get_amd_iommu_from_dev(dev); + struct pci_dev *pdev; int ret; /* @@ -2517,7 +2501,23 @@ static int amd_iommu_attach_device(struct iommu_domain *dom, } #endif - iommu_completion_wait(iommu); + pdev = dev_is_pci(dev_data->dev) ? to_pci_dev(dev_data->dev) : NULL; + if (pdev && pdom_is_sva_capable(domain)) { + pdev_enable_caps(pdev); + + /* + * Device can continue to function even if IOPF + * enablement failed. Hence in error path just + * disable device PRI support. + */ + if (amd_iommu_iopf_add_device(iommu, dev_data)) + pdev_disable_cap_pri(pdev); + } else if (pdev) { + pdev_enable_cap_ats(pdev); + } + + /* Update device table */ + amd_iommu_dev_update_dte(dev_data, true); return ret; } diff --git a/drivers/iommu/amd/ppr.c b/drivers/iommu/amd/ppr.c index 31d98a2a11a6e9..7c67d69f0b8cad 100644 --- a/drivers/iommu/amd/ppr.c +++ b/drivers/iommu/amd/ppr.c @@ -248,40 +248,26 @@ void amd_iommu_page_response(struct device *dev, struct iopf_fault *evt, int amd_iommu_iopf_add_device(struct amd_iommu *iommu, struct iommu_dev_data *dev_data) { - unsigned long flags; int ret = 0; if (!dev_data->pri_enabled) return ret; - raw_spin_lock_irqsave(&iommu->lock, flags); - - if (!iommu->iopf_queue) { - ret = -EINVAL; - goto out_unlock; - } + if (!iommu->iopf_queue) + return -EINVAL; ret = iopf_queue_add_device(iommu->iopf_queue, dev_data->dev); if (ret) - goto out_unlock; + return ret; dev_data->ppr = true; - -out_unlock: - raw_spin_unlock_irqrestore(&iommu->lock, flags); - return ret; + return 0; } /* Its assumed that caller has verified that device was added to iopf queue */ void amd_iommu_iopf_remove_device(struct amd_iommu *iommu, struct iommu_dev_data *dev_data) { - unsigned long flags; - - raw_spin_lock_irqsave(&iommu->lock, flags); - iopf_queue_remove_device(iommu->iopf_queue, dev_data->dev); dev_data->ppr = false; - - raw_spin_unlock_irqrestore(&iommu->lock, flags); }