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iommu/vt-d: Ratelimit fault handler

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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: 0ac2491f57 ('x86, dmar: move page fault handling code to dmar.c')
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Alex Williamson 2016-03-17 14:12:25 -06:00 committed by Joerg Roedel
parent 9735a22799
commit c43fce4eeb
1 changed files with 22 additions and 11 deletions
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33
drivers/iommu/dmar.c
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@ -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))