From 0c40bfb4c2dfad00a15337bb6213f92a797e3695 Mon Sep 17 00:00:00 2001 From: Dave Jiang Date: Fri, 7 Apr 2023 13:31:28 -0700 Subject: [PATCH] dmaengine: idxd: make misc interrupt one shot Current code continuously processes the interrupt as long as the hardware is setting the status bit. There's no reason to do that since the threaded handler will get called again if another interrupt is asserted. Also through testing, it has shown that if a misprogrammed (or malicious) agent can continuously submit descriptors with bad completion record and causes errors to be reported via the misc interrupt. Continuous processing by the thread can cause software hang watchdog to kick off since the thread isn't giving up the CPU. Reported-by: Sanjay Kumar Tested-by: Tony Zhu Signed-off-by: Dave Jiang Co-developed-by: Fenghua Yu Signed-off-by: Fenghua Yu Link: https://lore.kernel.org/r/20230407203143.2189681-2-fenghua.yu@intel.com Signed-off-by: Vinod Koul --- drivers/dma/idxd/irq.c | 38 ++++++++++++-------------------------- 1 file changed, 12 insertions(+), 26 deletions(-) diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c index aa314ebec587..0d639303b515 100644 --- a/drivers/dma/idxd/irq.c +++ b/drivers/dma/idxd/irq.c @@ -217,13 +217,22 @@ static void idxd_int_handle_revoke(struct work_struct *work) kfree(revoke); } -static int process_misc_interrupts(struct idxd_device *idxd, u32 cause) +irqreturn_t idxd_misc_thread(int vec, void *data) { + struct idxd_irq_entry *irq_entry = data; + struct idxd_device *idxd = ie_to_idxd(irq_entry); struct device *dev = &idxd->pdev->dev; union gensts_reg gensts; u32 val = 0; int i; bool err = false; + u32 cause; + + cause = ioread32(idxd->reg_base + IDXD_INTCAUSE_OFFSET); + if (!cause) + return IRQ_NONE; + + iowrite32(cause, idxd->reg_base + IDXD_INTCAUSE_OFFSET); if (cause & IDXD_INTC_HALT_STATE) goto halt; @@ -301,7 +310,7 @@ static int process_misc_interrupts(struct idxd_device *idxd, u32 cause) val); if (!err) - return 0; + goto out; halt: gensts.bits = ioread32(idxd->reg_base + IDXD_GENSTATS_OFFSET); @@ -324,33 +333,10 @@ halt: "idxd halted, need %s.\n", gensts.reset_type == IDXD_DEVICE_RESET_FLR ? "FLR" : "system reset"); - return -ENXIO; } } - return 0; -} - -irqreturn_t idxd_misc_thread(int vec, void *data) -{ - struct idxd_irq_entry *irq_entry = data; - struct idxd_device *idxd = ie_to_idxd(irq_entry); - int rc; - u32 cause; - - cause = ioread32(idxd->reg_base + IDXD_INTCAUSE_OFFSET); - if (cause) - iowrite32(cause, idxd->reg_base + IDXD_INTCAUSE_OFFSET); - - while (cause) { - rc = process_misc_interrupts(idxd, cause); - if (rc < 0) - break; - cause = ioread32(idxd->reg_base + IDXD_INTCAUSE_OFFSET); - if (cause) - iowrite32(cause, idxd->reg_base + IDXD_INTCAUSE_OFFSET); - } - +out: return IRQ_HANDLED; } -- 2.25.1