Messages in this thread Patch in this message | | | Date | Thu, 11 Jun 2009 20:05:11 -0700 | From | Chris Wright <> | Subject | [PATCH 2/2] amd-iommu: initialization fixes |
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If the kernel in initialized w/out coming out of reset (e.g. kexec/kdump), the prior kernel may leave the IOMMU running. Here's some fixes just to ensure all initialization is done in a sane manner.
1) disable IOMMU when discovered, will get renabled after it's set up 2) disable event log handling while setting up the event log buffer. the spec says: Software Note: If EventLen or EventBase is changed while the EventLogRun=1, the IOMMU behavior is undefined. 3) ensure the head/tail event log buffer pointers are initialized to zero
Signed-off-by: Chris Wright <chrisw@sous-sol.org> --- arch/x86/kernel/amd_iommu_init.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)
--- a/arch/x86/kernel/amd_iommu_init.c +++ b/arch/x86/kernel/amd_iommu_init.c @@ -252,6 +252,11 @@ static void __init iommu_enable(struct a iommu_feature_enable(iommu, CONTROL_IOMMU_EN); } +static void __init iommu_disable(struct amd_iommu *iommu) +{ + iommu_feature_disable(iommu, CONTROL_IOMMU_EN); +} + /* Function to enable IOMMU event logging and event interrupts */ static void __init iommu_enable_event_logging(struct amd_iommu *iommu) { @@ -259,6 +264,12 @@ static void __init iommu_enable_event_lo iommu_feature_enable(iommu, CONTROL_EVT_INT_EN); } +static void __init iommu_disable_event_logging(struct amd_iommu *iommu) +{ + iommu_feature_disable(iommu, CONTROL_EVT_INT_EN); + iommu_feature_disable(iommu, CONTROL_EVT_LOG_EN); +} + /* * mapping and unmapping functions for the IOMMU MMIO space. Each AMD IOMMU in * the system has one. @@ -453,12 +464,19 @@ static u8 * __init alloc_event_buffer(st if (iommu->evt_buf == NULL) return NULL; + /* disable event logging while setting it up */ + iommu_disable_event_logging(iommu); + entry = (u64)virt_to_phys(iommu->evt_buf) | EVT_LEN_MASK; memcpy_toio(iommu->mmio_base + MMIO_EVT_BUF_OFFSET, &entry, sizeof(entry)); iommu->evt_buf_size = EVT_BUFFER_SIZE; + /* set head and tail to zero manually */ + writel(0x00, iommu->mmio_base + MMIO_EVT_HEAD_OFFSET); + writel(0x00, iommu->mmio_base + MMIO_EVT_TAIL_OFFSET); + return iommu->evt_buf; } @@ -713,6 +731,9 @@ static int __init init_iommu_one(struct if (!iommu->mmio_base) return -ENOMEM; + /* disable IOMMU in case it was left on */ + iommu_disable(iommu); + iommu_set_device_table(iommu); iommu->cmd_buf = alloc_command_buffer(iommu); if (!iommu->cmd_buf)
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