From: Don Dutile <ddutile@redhat.com> Date: Tue, 1 Dec 2009 23:42:57 -0500 Subject: [pci] intel-iommu: fix for isoch dmar w/no tlb space Message-id: <4B15AA01.6030707@redhat.com> Patchwork-id: 21631 O-Subject: [RHEL5.5 PATCH V2] 3/9: AZALIA sound workaround for Isoch DMAR w-no TLB space Bugzilla: 516811 518103 RH-Acked-by: Chris Wright <chrisw@redhat.com> RH-Acked-by: Prarit Bhargava <prarit@redhat.com> V2 just changed the title. BZ 516727 (F12's bz: 490477) Backport of following commit: intel-iommu: Yet another BIOS workaround: Isoch DMAR unit with no TLB space commit e0fc7e0b4b5e69616f10a894ab9afff3c64be74e 0/9 states build & tests. Please review & ACK. - Don >From 1c02c4804238465aa914018e37ae666cc791ee92 Mon Sep 17 00:00:00 2001 From: Donald Dutile <ddutile@redhat.com> Date: Mon, 16 Nov 2009 17:46:47 -0500 Subject: [PATCH 3/9] INTEL_IOMMU: AZALIA Sound workaround diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c index 7898263..9cb7f43 100644 --- a/drivers/pci/intel-iommu.c +++ b/drivers/pci/intel-iommu.c @@ -47,6 +47,7 @@ #define IS_GFX_DEVICE(pdev) ((pdev->class >> 16) == PCI_BASE_CLASS_DISPLAY) #define IS_ISA_DEVICE(pdev) ((pdev->class >> 8) == PCI_CLASS_BRIDGE_ISA) +#define IS_AZALIA(pdev) ((pdev)->vendor == 0x8086 && (pdev)->device == 0x3a3e) #define IOAPIC_RANGE_START (0xfee00000) #define IOAPIC_RANGE_END (0xfeefffff) @@ -93,6 +94,7 @@ static inline unsigned long virt_to_dma_pfn(void *p) /* global iommu list, set NULL for ignored DMAR units */ static struct intel_iommu **g_iommus; +static void __init check_tylersburg_isoch(void); static int rwbf_quirk; /* @@ -1934,6 +1936,9 @@ error: } static int iommu_identity_mapping; +#define IDENTMAP_ALL 1 +#define IDENTMAP_GFX 2 +#define IDENTMAP_AZALIA 4 static int iommu_domain_identity_map(struct dmar_domain *domain, unsigned long long start, @@ -2164,8 +2169,14 @@ static int domain_add_dev_info(struct dmar_domain *domain, static int iommu_should_identity_map(struct pci_dev *pdev, int startup) { - if (iommu_identity_mapping == 2) - return IS_GFX_DEVICE(pdev); + if ((iommu_identity_mapping & IDENTMAP_AZALIA) && IS_AZALIA(pdev)) + return 1; + + if ((iommu_identity_mapping & IDENTMAP_GFX) && IS_GFX_DEVICE(pdev)) + return 1; + + if (!(iommu_identity_mapping & IDENTMAP_ALL)) + return 0; /* * We want to start off with all devices in the 1:1 domain, and @@ -2346,11 +2357,14 @@ int __init init_dmars(void) } if (iommu_pass_through) - iommu_identity_mapping = 1; + iommu_identity_mapping |= IDENTMAP_ALL; + #ifdef CONFIG_DMAR_BROKEN_GFX_WA - else - iommu_identity_mapping = 2; + iommu_identity_mapping |= IDENTMAP_GFX; #endif + + check_tylersburg_isoch(); + /* * If pass through is not set or not enabled, setup context entries for * identity mappings for rmrr, gfx, and isa and may fall back to static @@ -3672,3 +3686,61 @@ static void __devinit quirk_iommu_rwbf(struct pci_dev *dev) DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2a40, quirk_iommu_rwbf); +/* On Tylersburg chipsets, some BIOSes have been known to enable the + ISOCH DMAR unit for the Azalia sound device, but not give it any + TLB entries, which causes it to deadlock. Check for that. We do + this in a function called from init_dmars(), instead of in a PCI + quirk, because we don't want to print the obnoxious "BIOS broken" + message if VT-d is actually disabled. +*/ +static void __init check_tylersburg_isoch(void) +{ + struct pci_dev *pdev; + uint32_t vtisochctrl; + + /* If there's no Azalia in the system anyway, forget it. */ + pdev = pci_get_device(PCI_VENDOR_ID_INTEL, 0x3a3e, NULL); + if (!pdev) + return; + pci_dev_put(pdev); + + /* System Management Registers. Might be hidden, in which case + we can't do the sanity check. But that's OK, because the + known-broken BIOSes _don't_ actually hide it, so far. */ + pdev = pci_get_device(PCI_VENDOR_ID_INTEL, 0x342e, NULL); + if (!pdev) + return; + + if (pci_read_config_dword(pdev, 0x188, &vtisochctrl)) { + pci_dev_put(pdev); + return; + } + + pci_dev_put(pdev); + + /* If Azalia DMA is routed to the non-isoch DMAR unit, fine. */ + if (vtisochctrl & 1) + return; + + /* Drop all bits other than the number of TLB entries */ + vtisochctrl &= 0x1c; + + /* If we have the recommended number of TLB entries (16), fine. */ + if (vtisochctrl == 0x10) + return; + + /* Zero TLB entries? You get to ride the short bus to school. */ + if (!vtisochctrl) { + printk(KERN_WARNING + "Your BIOS is broken; DMA routed to ISOCH DMAR unit but no TLB space.\n" + "BIOS vendor: %s; Ver: %s; Product Version: %s\n", + dmi_get_system_info(DMI_BIOS_VENDOR), + dmi_get_system_info(DMI_BIOS_VERSION), + dmi_get_system_info(DMI_PRODUCT_VERSION)); + iommu_identity_mapping |= IDENTMAP_AZALIA; + return; + } + + printk(KERN_WARNING "DMAR: Recommended TLB entries for ISOCH unit is 16; your BIOS set %d\n", + vtisochctrl); +}