From c5cca146aa03e1f60fb179df65f0dbaf17bc64ed Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Fri, 9 Oct 2009 18:31:20 +0200 Subject: [PATCH] x86/amd-iommu: Workaround for erratum 63 There is an erratum for IOMMU hardware which documents undefined behavior when forwarding SMI requests from peripherals and the DTE of that peripheral has a sysmgt value of 01b. This problem caused weird IO_PAGE_FAULTS in my case. This patch implements the suggested workaround for that erratum into the AMD IOMMU driver. The erratum is documented with number 63. Cc: stable@kernel.org Signed-off-by: Joerg Roedel --- arch/x86/include/asm/amd_iommu.h | 1 + arch/x86/kernel/amd_iommu.c | 2 ++ arch/x86/kernel/amd_iommu_init.c | 22 ++++++++++++++++++++++ 3 files changed, 25 insertions(+) diff --git a/arch/x86/include/asm/amd_iommu.h b/arch/x86/include/asm/amd_iommu.h index bdf96f119f06..9dbd4030f0cd 100644 --- a/arch/x86/include/asm/amd_iommu.h +++ b/arch/x86/include/asm/amd_iommu.h @@ -30,6 +30,7 @@ extern irqreturn_t amd_iommu_int_handler(int irq, void *data); extern void amd_iommu_flush_all_domains(void); extern void amd_iommu_flush_all_devices(void); extern void amd_iommu_shutdown(void); +extern void amd_iommu_apply_erratum_63(u16 devid); #else static inline int amd_iommu_init(void) { return -ENODEV; } static inline void amd_iommu_detect(void) { } diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c index 6c99f5037801..f95dfe526444 100644 --- a/arch/x86/kernel/amd_iommu.c +++ b/arch/x86/kernel/amd_iommu.c @@ -1114,6 +1114,8 @@ static void __detach_device(struct protection_domain *domain, u16 devid) amd_iommu_dev_table[devid].data[1] = 0; amd_iommu_dev_table[devid].data[2] = 0; + amd_iommu_apply_erratum_63(devid); + /* decrease reference counter */ domain->dev_cnt -= 1; diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c index c1b17e97252e..498c8c79aaa5 100644 --- a/arch/x86/kernel/amd_iommu_init.c +++ b/arch/x86/kernel/amd_iommu_init.c @@ -509,6 +509,26 @@ static void set_dev_entry_bit(u16 devid, u8 bit) amd_iommu_dev_table[devid].data[i] |= (1 << _bit); } +static int get_dev_entry_bit(u16 devid, u8 bit) +{ + int i = (bit >> 5) & 0x07; + int _bit = bit & 0x1f; + + return (amd_iommu_dev_table[devid].data[i] & (1 << _bit)) >> _bit; +} + + +void amd_iommu_apply_erratum_63(u16 devid) +{ + int sysmgt; + + sysmgt = get_dev_entry_bit(devid, DEV_ENTRY_SYSMGT1) | + (get_dev_entry_bit(devid, DEV_ENTRY_SYSMGT2) << 1); + + if (sysmgt == 0x01) + set_dev_entry_bit(devid, DEV_ENTRY_IW); +} + /* Writes the specific IOMMU for a device into the rlookup table */ static void __init set_iommu_for_device(struct amd_iommu *iommu, u16 devid) { @@ -537,6 +557,8 @@ static void __init set_dev_entry_from_acpi(struct amd_iommu *iommu, if (flags & ACPI_DEVFLAG_LINT1) set_dev_entry_bit(devid, DEV_ENTRY_LINT1_PASS); + amd_iommu_apply_erratum_63(devid); + set_iommu_for_device(iommu, devid); } -- 2.20.1