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authorAlex Williamson <alex.williamson@redhat.com>2016-03-17 23:12:25 +0300
committerJoerg Roedel <jroedel@suse.de>2016-04-05 17:21:49 +0300
commitc43fce4eebae257ca413733690e2076757282093 (patch)
tree31120baca6aa7bb297520e1806dbddd827eccb26 /drivers/iommu/dmar.c
parent9735a22799b9214d17d3c231fe377fc852f042e9 (diff)
downloadlinux-c43fce4eebae257ca413733690e2076757282093.tar.xz
iommu/vt-d: Ratelimit fault handler
Fault rates can easily overwhelm the console and make the system unresponsive. Ratelimit to allow an opportunity for maintenance. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Fixes: 0ac2491f57af ('x86, dmar: move page fault handling code to dmar.c') Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'drivers/iommu/dmar.c')
-rw-r--r--drivers/iommu/dmar.c33
1 files changed, 22 insertions, 11 deletions
diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 8ffd7568fc91..8f8bfffbf1e6 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -1602,10 +1602,17 @@ irqreturn_t dmar_fault(int irq, void *dev_id)
int reg, fault_index;
u32 fault_status;
unsigned long flag;
+ bool ratelimited;
+ static DEFINE_RATELIMIT_STATE(rs,
+ DEFAULT_RATELIMIT_INTERVAL,
+ DEFAULT_RATELIMIT_BURST);
+
+ /* Disable printing, simply clear the fault when ratelimited */
+ ratelimited = !__ratelimit(&rs);
raw_spin_lock_irqsave(&iommu->register_lock, flag);
fault_status = readl(iommu->reg + DMAR_FSTS_REG);
- if (fault_status)
+ if (fault_status && !ratelimited)
pr_err("DRHD: handling fault status reg %x\n", fault_status);
/* TBD: ignore advanced fault log currently */
@@ -1627,24 +1634,28 @@ irqreturn_t dmar_fault(int irq, void *dev_id)
if (!(data & DMA_FRCD_F))
break;
- fault_reason = dma_frcd_fault_reason(data);
- type = dma_frcd_type(data);
+ if (!ratelimited) {
+ fault_reason = dma_frcd_fault_reason(data);
+ type = dma_frcd_type(data);
- data = readl(iommu->reg + reg +
- fault_index * PRIMARY_FAULT_REG_LEN + 8);
- source_id = dma_frcd_source_id(data);
+ data = readl(iommu->reg + reg +
+ fault_index * PRIMARY_FAULT_REG_LEN + 8);
+ source_id = dma_frcd_source_id(data);
+
+ guest_addr = dmar_readq(iommu->reg + reg +
+ fault_index * PRIMARY_FAULT_REG_LEN);
+ guest_addr = dma_frcd_page_addr(guest_addr);
+ }
- guest_addr = dmar_readq(iommu->reg + reg +
- fault_index * PRIMARY_FAULT_REG_LEN);
- guest_addr = dma_frcd_page_addr(guest_addr);
/* clear the fault */
writel(DMA_FRCD_F, iommu->reg + reg +
fault_index * PRIMARY_FAULT_REG_LEN + 12);
raw_spin_unlock_irqrestore(&iommu->register_lock, flag);
- dmar_fault_do_one(iommu, type, fault_reason,
- source_id, guest_addr);
+ if (!ratelimited)
+ dmar_fault_do_one(iommu, type, fault_reason,
+ source_id, guest_addr);
fault_index++;
if (fault_index >= cap_num_fault_regs(iommu->cap))