From c2ff5cf5294bcbd7fa50f7d860e90a66db7e5059 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Tue, 16 Oct 2012 14:52:51 +0200 Subject: [PATCH] iommu/amd: Work around wrong IOAPIC device-id in IVRS table On some systems the BIOS puts the wrong device-id for the IO-APIC into the IVRS table. The result is that interrupt remapping is not working for the IO-APIC irqs. This usually means a kernel panic at boot because the timer is not working. Fix this kernel panic by disabling interrupt remapping if this problem is discovered in the IVRS table. Reported-by: Andrew Oakley Signed-off-by: Joerg Roedel --- drivers/iommu/amd_iommu_init.c | 39 ++++++++++++++++++++++++++++------ 1 file changed, 32 insertions(+), 7 deletions(-) diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c index 18b0d99bd4d6..81837b0710a9 100644 --- a/drivers/iommu/amd_iommu_init.c +++ b/drivers/iommu/amd_iommu_init.c @@ -1599,21 +1599,46 @@ static void __init free_on_init_error(void) #endif } +/* SB IOAPIC is always on this device in AMD systems */ +#define IOAPIC_SB_DEVID ((0x00 << 8) | PCI_DEVFN(0x14, 0)) + static bool __init check_ioapic_information(void) { + bool ret, has_sb_ioapic; int idx; - for (idx = 0; idx < nr_ioapics; idx++) { - int id = mpc_ioapic_id(idx); + has_sb_ioapic = false; + ret = false; - if (get_ioapic_devid(id) < 0) { - pr_err(FW_BUG "AMD-Vi: IO-APIC[%d] not in IVRS table\n", id); - pr_err("AMD-Vi: Disabling interrupt remapping due to BIOS Bug\n"); - return false; + for (idx = 0; idx < nr_ioapics; idx++) { + int devid, id = mpc_ioapic_id(idx); + + devid = get_ioapic_devid(id); + if (devid < 0) { + pr_err(FW_BUG "AMD-Vi: IOAPIC[%d] not in IVRS table\n", id); + ret = false; + } else if (devid == IOAPIC_SB_DEVID) { + has_sb_ioapic = true; + ret = true; } } - return true; + if (!has_sb_ioapic) { + /* + * We expect the SB IOAPIC to be listed in the IVRS + * table. The system timer is connected to the SB IOAPIC + * and if we don't have it in the list the system will + * panic at boot time. This situation usually happens + * when the BIOS is buggy and provides us the wrong + * device id for the IOAPIC in the system. + */ + pr_err(FW_BUG "AMD-Vi: No southbridge IOAPIC found in IVRS table\n"); + } + + if (!ret) + pr_err("AMD-Vi: Disabling interrupt remapping due to BIOS Bug(s)\n"); + + return ret; } static void __init free_dma_resources(void) -- 2.39.2