From f32ab7547161b9fa7ebfbc4f18ea1eb3fd49fe25 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=3D=3FUTF-8=3Fq=3FChristian=3D20K=3DC3=3DB6nig=3F=3D?= Date: Thu, 11 Jan 2018 14:23:29 +0100 Subject: [PATCH 1/2] x86/PCI: Add "pci=big_root_window" option for AMD 64-bit windows MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Only try to enable a 64-bit window on AMD CPUs when "pci=big_root_window" is specified. This taints the kernel because the new 64-bit window uses address space we don't know anything about, and it may contain unreported devices or memory that would conflict with the window. The pci_amd_enable_64bit_bar() quirk that enables the window is specific to AMD CPUs. The generic solution would be to have the firmware enable the window and describe it in the host bridge's _CRS method, or at least describe it in the _PRS method so the OS would have the option of enabling it. Signed-off-by: Christian König [bhelgaas: changelog, extend doc, mention taint in dmesg] Signed-off-by: Bjorn Helgaas --- Documentation/admin-guide/kernel-parameters.txt | 6 ++++++ arch/x86/include/asm/pci_x86.h | 1 + arch/x86/pci/common.c | 5 +++++ arch/x86/pci/fixup.c | 7 ++++++- 4 files changed, 18 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 6571fbfdb2a1..619638362416 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3094,6 +3094,12 @@ pcie_scan_all Scan all possible PCIe devices. Otherwise we only look for one device below a PCIe downstream port. + big_root_window Try to add a big 64bit memory window to the PCIe + root complex on AMD CPUs. Some GFX hardware + can resize a BAR to allow access to all VRAM. + Adding the window is slightly risky (it may + conflict with unreported devices), so this + taints the kernel. pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power Management. diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h index 7a5d6695abd3..eb66fa9cd0fc 100644 --- a/arch/x86/include/asm/pci_x86.h +++ b/arch/x86/include/asm/pci_x86.h @@ -38,6 +38,7 @@ do { \ #define PCI_NOASSIGN_ROMS 0x80000 #define PCI_ROOT_NO_CRS 0x100000 #define PCI_NOASSIGN_BARS 0x200000 +#define PCI_BIG_ROOT_WINDOW 0x400000 extern unsigned int pci_probe; extern unsigned long pirq_table_addr; diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c index 7a5350d08cef..563049c483a1 100644 --- a/arch/x86/pci/common.c +++ b/arch/x86/pci/common.c @@ -594,6 +594,11 @@ char *__init pcibios_setup(char *str) } else if (!strcmp(str, "nocrs")) { pci_probe |= PCI_ROOT_NO_CRS; return NULL; +#ifdef CONFIG_PHYS_ADDR_T_64BIT + } else if (!strcmp(str, "big_root_window")) { + pci_probe |= PCI_BIG_ROOT_WINDOW; + return NULL; +#endif } else if (!strcmp(str, "earlydump")) { pci_early_dump_regs = 1; return NULL; diff --git a/arch/x86/pci/fixup.c b/arch/x86/pci/fixup.c index e663d6bf1328..8bad19c7473d 100644 --- a/arch/x86/pci/fixup.c +++ b/arch/x86/pci/fixup.c @@ -667,6 +667,9 @@ static void pci_amd_enable_64bit_bar(struct pci_dev *dev) struct resource *res, *conflict; struct pci_dev *other; + if (!(pci_probe & PCI_BIG_ROOT_WINDOW)) + return; + /* Check that we are the only device of that type */ other = pci_get_device(dev->vendor, dev->device, NULL); if (other != dev || @@ -714,7 +717,9 @@ static void pci_amd_enable_64bit_bar(struct pci_dev *dev) res->start = conflict->end + 1; } - dev_info(&dev->dev, "adding root bus resource %pR\n", res); + dev_info(&dev->dev, "adding root bus resource %pR (tainting kernel)\n", + res); + add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK); base = ((res->start >> 8) & AMD_141b_MMIO_BASE_MMIOBASE_MASK) | AMD_141b_MMIO_BASE_RE_MASK | AMD_141b_MMIO_BASE_WE_MASK; From 03a551734cfc2b93f83950a595974e3c9cbd82fd Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=3D=3FUTF-8=3Fq=3FChristian=3D20K=3DC3=3DB6nig=3F=3D?= Date: Thu, 11 Jan 2018 14:23:30 +0100 Subject: [PATCH 2/2] x86/PCI: Move and shrink AMD 64-bit window to avoid conflict MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Avoid problems with BIOS implementations which don't report all used resources to the OS by only allocating a 256GB window directly below the hardware limit (from the BKDG, sec 2.4.6). Fixes a silent reboot loop reported by Aaro Koskinen on an AMD-based MSI MS-7699/760GA-P43(FX) system. This was apparently caused by RAM or other unreported hardware that conflicted with the new window. Link: https://support.amd.com/TechDocs/49125_15h_Models_30h-3Fh_BKDG.pdf Link: https://lkml.kernel.org/r/20180105220412.fzpwqe4zljdawr36@darkstar.musicnaut.iki.fi Fixes: fa564ad96366 ("x86/PCI: Enable a 64bit BAR on AMD Family 15h (Models 00-1f, 30-3f, 60-7f)") Reported-by: Aaro Koskinen Signed-off-by: Christian König [bhelgaas: changelog, comment, Fixes:] Signed-off-by: Bjorn Helgaas --- arch/x86/pci/fixup.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/arch/x86/pci/fixup.c b/arch/x86/pci/fixup.c index 8bad19c7473d..f6a26e3cb476 100644 --- a/arch/x86/pci/fixup.c +++ b/arch/x86/pci/fixup.c @@ -662,10 +662,11 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x2033, quirk_no_aersid); */ static void pci_amd_enable_64bit_bar(struct pci_dev *dev) { - unsigned i; u32 base, limit, high; - struct resource *res, *conflict; struct pci_dev *other; + struct resource *res; + unsigned i; + int r; if (!(pci_probe & PCI_BIG_ROOT_WINDOW)) return; @@ -702,19 +703,20 @@ static void pci_amd_enable_64bit_bar(struct pci_dev *dev) if (!res) return; + /* + * Allocate a 256GB window directly below the 0xfd00000000 hardware + * limit (see AMD Family 15h Models 30h-3Fh BKDG, sec 2.4.6). + */ res->name = "PCI Bus 0000:00"; res->flags = IORESOURCE_PREFETCH | IORESOURCE_MEM | IORESOURCE_MEM_64 | IORESOURCE_WINDOW; - res->start = 0x100000000ull; + res->start = 0xbd00000000ull; res->end = 0xfd00000000ull - 1; - /* Just grab the free area behind system memory for this */ - while ((conflict = request_resource_conflict(&iomem_resource, res))) { - if (conflict->end >= res->end) { - kfree(res); - return; - } - res->start = conflict->end + 1; + r = request_resource(&iomem_resource, res); + if (r) { + kfree(res); + return; } dev_info(&dev->dev, "adding root bus resource %pR (tainting kernel)\n",