Commit abf051be authored Nov 16, 2016 by Vaibhav Jain Committed by Michael Ellerman Nov 18, 2016

cxl: Do adapter fence check before handling afu interrupt



If an afu interrupt is in flight when an eeh error is triggered the
control still reaches the function native_irq_multiplexed and the
PE-Handle read from the CXL_PSL_PEHandle_An register is 0xffff. The
function then erroneously assumes that the interrupt belonged to a
detached context and generates a warning with full stack dump in the
kernel log complaining:

"Unable to demultiplex CXL PSL IRQ for PE 65535 DSISR ffffffff DAR
ffffffff. (Possible AFU HW issue - was a term/remove acked with
outstanding transactions"

To fix this the patch adds new code to the function
native_irq_multiplexed function to compares the read value of register
CXL_PSL_PEHandle_An to ~0ULL. If true then logs a warning message
saying that the interrupt is being ignored and returns IRQ_HANDLED from
the irq handler.

Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

parent bb81733d

drivers/misc/cxl/native.c

+12 −3

Original line number	Diff line number	Diff line
		@@ -931,9 +931,18 @@ static irqreturn_t native_irq_multiplexed(int irq, void *data)
		struct cxl_afu *afu = data;
		struct cxl_context *ctx;
		struct cxl_irq_info irq_info;
		int ph = cxl_p2n_read(afu, CXL_PSL_PEHandle_An) & 0xffff;
		int ret;

		u64 phreg = cxl_p2n_read(afu, CXL_PSL_PEHandle_An);
		int ph, ret;

		/* check if eeh kicked in while the interrupt was in flight */
		if (unlikely(phreg == ~0ULL)) {
		dev_warn(&afu->dev,
		"Ignoring slice interrupt(%d) due to fenced card",
		irq);
		return IRQ_HANDLED;
		}
		/* Mask the pe-handle from register value */
		ph = phreg & 0xffff;
		if ((ret = native_get_irq_info(afu, &irq_info))) {
		WARN(1, "Unable to get CXL IRQ Info: %i\n", ret);
		return fail_psl_irq(afu, &irq_info);

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