Please consider applying this patch, I would consider it critical for x86-64. The 2.6.0 x86-64 IOMMU code unfortunately had a few problems, leading to non booting systems and in a few cases to data corruption. It fixes a two serious bugs in handling special kinds of scatter gather lists in pci_map_sg. AGP was completely broken with IOMMU because of a wrong #ifdef. Fix that. One TLB flush optimization I did a long time ago seems to break on some 3ware boards (who require IOMMU because they don't support 64bit addresses). The breakage lead to data corruption. This patch diables the optimization for now and fixes a potential SMP race in the flush code too. The TLB flush is done in a slower, but more reliable way now too. This patch fixes them. Please consider applying, because some of these problems hit quite many people. This also disables the IOMMU_DEBUG in the defconfig. A lot of people were using the IOMMU when they didn't need to, which multiplied the problems. IOMMU merge is disabled for now. This was an experimental optimization which helped with some block devices, but for production it seems to be better to disable it for now because there are some questionable corner cases when the IOMMU aperture fragments. The same is done for IOMMU SAC force, which was related to that. i386 has quite broken semantics for pci_alloc_consistent(). It uses the standard device DMA mask instead of the consistent mask. Make us bug-to-bug compatible here. This fixes problems with some sound drivers that don't support full 32bit addressing. /dev/null | 0 arch/x86_64/Kconfig | 1 arch/x86_64/defconfig | 2 - arch/x86_64/kernel/pci-gart.c | 53 +++++++++++++++++++++++------------------ arch/x86_64/kernel/pci-nommu.c | 2 + include/asm-x86_64/io.h | 4 +-- 6 files changed, 36 insertions(+), 26 deletions(-) diff -puN arch/x86_64/defconfig~x86_64-01 arch/x86_64/defconfig --- 25/arch/x86_64/defconfig~x86_64-01 2003-12-23 23:52:56.000000000 -0800 +++ 25-akpm/arch/x86_64/defconfig 2003-12-23 23:52:56.000000000 -0800 @@ -743,7 +743,7 @@ CONFIG_MAGIC_SYSRQ=y # CONFIG_INIT_DEBUG is not set # CONFIG_DEBUG_INFO is not set # CONFIG_FRAME_POINTER is not set -CONFIG_IOMMU_DEBUG=y +# CONFIG_IOMMU_DEBUG is not set CONFIG_IOMMU_LEAK=y CONFIG_MCE_DEBUG=y diff -puN -L arch/x86_64/defconfig-CONFIG /dev/null /dev/null diff -puN arch/x86_64/Kconfig~x86_64-01 arch/x86_64/Kconfig --- 25/arch/x86_64/Kconfig~x86_64-01 2003-12-23 23:52:56.000000000 -0800 +++ 25-akpm/arch/x86_64/Kconfig 2003-12-23 23:52:56.000000000 -0800 @@ -511,6 +511,7 @@ config FRAME_POINTER Normally you should say N. config IOMMU_DEBUG + depends on GART_IOMMU && DEBUG_KERNEL bool "Force IOMMU to on" help Force the IOMMU to on even when you have less than 4GB of memory and add diff -puN -L arch/x86_64/Kconfig-IOMMU /dev/null /dev/null diff -puN arch/x86_64/kernel/pci-gart.c~x86_64-01 arch/x86_64/kernel/pci-gart.c --- 25/arch/x86_64/kernel/pci-gart.c~x86_64-01 2003-12-23 23:52:56.000000000 -0800 +++ 25-akpm/arch/x86_64/kernel/pci-gart.c 2003-12-23 23:52:56.000000000 -0800 @@ -44,12 +44,13 @@ static int no_agp; #ifdef CONFIG_IOMMU_DEBUG int panic_on_overflow = 1; int force_iommu = 1; -int sac_force_size = 0; #else -int panic_on_overflow = 1; /* for testing */ +int panic_on_overflow = 0; int force_iommu = 0; -int sac_force_size = 256*1024*1024; #endif +int iommu_merge = 0; +int iommu_sac_force = 0; +int iommu_fullflush = 1; /* Allocation bitmap for the remapping area */ static spinlock_t iommu_bitmap_lock = SPIN_LOCK_UNLOCKED; @@ -125,7 +126,7 @@ static void free_iommu(unsigned long off /* * Use global flush state to avoid races with multiple flushers. */ -static void __flush_gart(struct pci_dev *dev) +static void flush_gart(struct pci_dev *dev) { unsigned long flags; int bus = dev ? dev->bus->number : -1; @@ -134,13 +135,17 @@ static void __flush_gart(struct pci_dev int i; spin_lock_irqsave(&iommu_bitmap_lock, flags); - /* recheck flush count inside lock */ - if (need_flush) { + if (need_flush || iommu_fullflush) { for (i = 0; northbridges[i]; i++) { + u32 w; if (bus >= 0 && !(cpu_isset_const(i, bus_cpumask))) continue; pci_write_config_dword(northbridges[i], 0x9c, northbridge_flush_word[i] | 1); + /* Make sure the hardware actually executed the flush. */ + do { + pci_read_config_dword(northbridges[i], 0x9c, &w); + } while (w & 1); flushed++; } if (!flushed) @@ -150,12 +155,6 @@ static void __flush_gart(struct pci_dev spin_unlock_irqrestore(&iommu_bitmap_lock, flags); } -static inline void flush_gart(struct pci_dev *dev) -{ - if (need_flush) - __flush_gart(dev); -} - /* * Allocate memory for a consistent mapping. * All mappings are consistent here, so this is just a wrapper around @@ -174,11 +173,16 @@ void *pci_alloc_consistent(struct pci_de } else { dma_mask = hwdev->consistent_dma_mask; } + if (dma_mask == 0) dma_mask = 0xffffffff; if (dma_mask < 0xffffffff || no_iommu) gfp |= GFP_DMA; + /* Kludge to make it bug-to-bug compatible with i386. i386 + uses the normal dma_mask for alloc_consistent. */ + dma_mask &= hwdev->dma_mask; + memory = (void *)__get_free_pages(gfp, get_order(size)); if (memory == NULL) { return NULL; @@ -394,7 +398,9 @@ static int __pci_map_cont(struct scatter for (i = start; i < stopat; i++) { struct scatterlist *s = &sg[i]; - unsigned long start_addr = s->dma_address; + unsigned long pages, addr; + unsigned long phys_addr = s->dma_address; + BUG_ON(i > start && s->offset); if (i == start) { *sout = *s; @@ -403,8 +409,10 @@ static int __pci_map_cont(struct scatter } else { sout->length += s->length; } - unsigned long addr = start_addr; - while (addr < start_addr + s->length) { + + addr = phys_addr; + pages = to_pages(s->offset, s->length); + while (pages--) { iommu_gatt_base[iommu_page] = GPTE_ENCODE(addr); SET_LEAK(iommu_page); addr += PAGE_SIZE; @@ -437,7 +445,7 @@ int pci_map_sg(struct pci_dev *dev, stru int out; int start; unsigned long pages = 0; - int need = 0; + int need = 0, nextneed; unsigned long size = 0; @@ -453,13 +461,14 @@ int pci_map_sg(struct pci_dev *dev, stru BUG_ON(s->length == 0); size += s->length; + nextneed = need_iommu(dev, addr, s->length); /* Handle the previous not yet processed entries */ if (i > start) { struct scatterlist *ps = &sg[i-1]; /* Can only merge when the last chunk ends on a page - boundary. */ - if (!force_iommu || !need || (i-1 > start && ps->offset) || + boundary and the new one doesn't have an offset. */ + if (!iommu_merge || !nextneed || !need || s->offset || (ps->offset + ps->length) % PAGE_SIZE) { if (pci_map_cont(sg, start, i, sg+out, pages, need) < 0) @@ -470,7 +479,7 @@ int pci_map_sg(struct pci_dev *dev, stru } } - need = need_iommu(dev, addr, s->length); + need = nextneed; pages += to_pages(s->offset, s->length); } if (pci_map_cont(sg, start, i, sg+out, pages, need) < 0) @@ -544,14 +553,12 @@ int pci_dma_supported(struct pci_dev *de Problem with this is that if we overflow the IOMMU area and return DAC as fallback address the device may not handle it correctly. - As a compromise we only do this if the IOMMU area is >= 256MB - which should make overflow unlikely enough. As a special case some controllers have a 39bit address mode that is as efficient as 32bit (aic79xx). Don't force SAC for these. Assume all masks <= 40 bits are of this type. Normally this doesn't make any difference, but gives more gentle handling of IOMMU overflow. */ - if (force_iommu && (mask > 0xffffffffffULL) && (iommu_size >= sac_force_size)){ + if (iommu_sac_force && (mask >= 0xffffffffffULL)) { printk(KERN_INFO "%s: Force SAC with mask %Lx\n", dev->slot_name,mask); return 0; } @@ -680,7 +687,7 @@ static int __init pci_iommu_init(void) unsigned long iommu_start; struct pci_dev *dev; -#ifndef CONFIG_AGP_AMD_8151 +#ifndef CONFIG_AGP_AMD64 no_agp = 1; #else /* Makefile puts PCI initialization via subsys_initcall first. */ diff -puN -L arch/x86_64/kernel/pci-gart.c-IOMMU /dev/null /dev/null diff -puN arch/x86_64/kernel/pci-nommu.c~x86_64-01 arch/x86_64/kernel/pci-nommu.c --- 25/arch/x86_64/kernel/pci-nommu.c~x86_64-01 2003-12-23 23:52:56.000000000 -0800 +++ 25-akpm/arch/x86_64/kernel/pci-nommu.c 2003-12-23 23:52:56.000000000 -0800 @@ -4,6 +4,8 @@ #include #include +int iommu_merge = 0; + /* * Dummy IO MMU functions */ diff -puN -L arch/x86_64/kernel/pci-nommu.c-IOMMU /dev/null /dev/null diff -puN include/asm-x86_64/io.h~x86_64-01 include/asm-x86_64/io.h --- 25/include/asm-x86_64/io.h~x86_64-01 2003-12-23 23:52:56.000000000 -0800 +++ 25-akpm/include/asm-x86_64/io.h 2003-12-23 23:52:56.000000000 -0800 @@ -304,8 +304,8 @@ out: /* Disable vmerge for now. Need to fix the block layer code to check for non iommu addresses first. When the IOMMU is force it is safe to enable. */ -extern int force_iommu; -#define BIO_VERMGE_BOUNDARY (force_iommu ? 4096 : 0) +extern int iommu_merge; +#define BIO_VMERGE_BOUNDARY (iommu_merge ? 4096 : 0) #endif /* __KERNEL__ */ diff -puN -L include/asm-x86_64/io.h-IOMMU /dev/null /dev/null _