diff options
| author | Joerg Roedel <joerg.roedel@amd.com> | 2012-04-12 14:12:00 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-06-10 00:36:10 +0900 |
| commit | c2fcf3a04bc4c9a9b97962b3b71c86ba393672e3 (patch) | |
| tree | 455495462a9c3443d1e2bc2d755294d8853f8947 /drivers/iommu | |
| parent | f9a07f3089169d943ba0e61e7670e61199020870 (diff) | |
iommu/amd: Add workaround for event log erratum
commit 3d06fca8d2aa3543030e40b95f1d62f9f5a03540 upstream.
Due to a recent erratum it can happen that the head pointer
of the event-log is updated before the actual event-log
entry is written. This patch implements the recommended
workaround.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/iommu')
| -rw-r--r-- | drivers/iommu/amd_iommu.c | 29 |
1 files changed, 23 insertions, 6 deletions
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c index 08f3eecb87a..d90a421e9ca 100644 --- a/drivers/iommu/amd_iommu.c +++ b/drivers/iommu/amd_iommu.c @@ -450,12 +450,27 @@ static void dump_command(unsigned long phys_addr) static void iommu_print_event(struct amd_iommu *iommu, void *__evt) { - u32 *event = __evt; - int type = (event[1] >> EVENT_TYPE_SHIFT) & EVENT_TYPE_MASK; - int devid = (event[0] >> EVENT_DEVID_SHIFT) & EVENT_DEVID_MASK; - int domid = (event[1] >> EVENT_DOMID_SHIFT) & EVENT_DOMID_MASK; - int flags = (event[1] >> EVENT_FLAGS_SHIFT) & EVENT_FLAGS_MASK; - u64 address = (u64)(((u64)event[3]) << 32) | event[2]; + int type, devid, domid, flags; + volatile u32 *event = __evt; + int count = 0; + u64 address; + +retry: + type = (event[1] >> EVENT_TYPE_SHIFT) & EVENT_TYPE_MASK; + devid = (event[0] >> EVENT_DEVID_SHIFT) & EVENT_DEVID_MASK; + domid = (event[1] >> EVENT_DOMID_SHIFT) & EVENT_DOMID_MASK; + flags = (event[1] >> EVENT_FLAGS_SHIFT) & EVENT_FLAGS_MASK; + address = (u64)(((u64)event[3]) << 32) | event[2]; + + if (type == 0) { + /* Did we hit the erratum? */ + if (++count == LOOP_TIMEOUT) { + pr_err("AMD-Vi: No event written to event log\n"); + return; + } + udelay(1); + goto retry; + } printk(KERN_ERR "AMD-Vi: Event logged ["); @@ -508,6 +523,8 @@ static void iommu_print_event(struct amd_iommu *iommu, void *__evt) default: printk(KERN_ERR "UNKNOWN type=0x%02x]\n", type); } + + memset(__evt, 0, 4 * sizeof(u32)); } static void iommu_poll_events(struct amd_iommu *iommu) |