AMD IOMMU: add event buffer allocation

This patch adds the allocation of a event buffer for each AMD IOMMU in
the system. The hardware will log events like device page faults or
other errors to this buffer once this is enabled.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index f2fa8dc..41ce8d5 100644 (file)
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -417,6 +417,30 @@ static void __init free_command_buffer(struct amd_iommu *iommu)
        free_pages((unsigned long)iommu->cmd_buf, get_order(CMD_BUFFER_SIZE));
 }
 
+/* allocates the memory where the IOMMU will log its events to */
+static u8 * __init alloc_event_buffer(struct amd_iommu *iommu)
+{
+       u64 entry;
+       iommu->evt_buf = (u8 *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
+                                               get_order(EVT_BUFFER_SIZE));
+
+       if (iommu->evt_buf == NULL)
+               return NULL;
+
+       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;
+
+       return iommu->evt_buf;
+}
+
+static void __init free_event_buffer(struct amd_iommu *iommu)
+{
+       free_pages((unsigned long)iommu->evt_buf, get_order(EVT_BUFFER_SIZE));
+}
+
 /* sets a specific bit in the device table entry. */
 static void set_dev_entry_bit(u16 devid, u8 bit)
 {
@@ -622,6 +646,7 @@ static int __init init_iommu_devices(struct amd_iommu *iommu)
 static void __init free_iommu_one(struct amd_iommu *iommu)
 {
        free_command_buffer(iommu);
+       free_event_buffer(iommu);
        iommu_unmap_mmio_space(iommu);
 }
 
@@ -661,6 +686,10 @@ static int __init init_iommu_one(struct amd_iommu *iommu, struct ivhd_header *h)
        if (!iommu->cmd_buf)
                return -ENOMEM;
 
+       iommu->evt_buf = alloc_event_buffer(iommu);
+       if (!iommu->evt_buf)
+               return -ENOMEM;
+
        init_iommu_from_pci(iommu);
        init_iommu_from_acpi(iommu, h);
        init_iommu_devices(iommu);

diff --git a/include/asm-x86/amd_iommu_types.h b/include/asm-x86/amd_iommu_types.h
index dcc4724..8b8cd0c 100644 (file)
--- a/include/asm-x86/amd_iommu_types.h
+++ b/include/asm-x86/amd_iommu_types.h
@@ -116,6 +116,10 @@
 #define MMIO_CMD_SIZE_SHIFT 56
 #define MMIO_CMD_SIZE_512 (0x9ULL << MMIO_CMD_SIZE_SHIFT)
 
+/* constants for event buffer handling */
+#define EVT_BUFFER_SIZE                8192 /* 512 entries */
+#define EVT_LEN_MASK           (0x9ULL << 56)
+
 #define PAGE_MODE_1_LEVEL 0x01
 #define PAGE_MODE_2_LEVEL 0x02
 #define PAGE_MODE_3_LEVEL 0x03
@@ -243,6 +247,11 @@ struct amd_iommu {
        /* size of command buffer */
        u32 cmd_buf_size;
 
+       /* event buffer virtual address */
+       u8 *evt_buf;
+       /* size of event buffer */
+       u32 evt_buf_size;
+
        /* if one, we need to send a completion wait command */
        int need_sync;