cxl: Return error to PSL if IRQ demultiplexing fails & print clearer warning

If an AFU has a hardware bug that causes it to acknowledge a context
terminate or remove while that context has outstanding transactions, it
is possible for the kernel to receive an interrupt for that context
after we have removed it from the context list.

The kernel will not be able to demultiplex the interrupt (or worse - if
we have already reallocated the process handle we could mis-attribute it
to the new context), and printed a big scary warning.

It did not acknowledge the interrupt, which would effectively halt
further translation fault processing on the PSL.

This patch makes the warning clearer about the likely cause of the issue
(i.e. hardware bug) to make it obvious to future AFU designers of what
needs to be fixed. It also prints out the process handle which can then
be matched up with hardware and software traces for debugging.

It also acknowledges the interrupt to the PSL with either an address
error or acknowledge, so that the PSL can continue with other
translations.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 7 insertions, 7 deletions

diff --git a/drivers/misc/cxl/native.c b/drivers/misc/cxl/native.c
index d47532e8f4f1..9a5a442269a8 100644
--- a/drivers/misc/cxl/native.c
+++ b/drivers/misc/cxl/native.c
@@ -637,18 +637,18 @@ int cxl_detach_process(struct cxl_context *ctx)
 	return detach_process_native_afu_directed(ctx);
 }
 
-int cxl_get_irq(struct cxl_context *ctx, struct cxl_irq_info *info)
+int cxl_get_irq(struct cxl_afu *afu, struct cxl_irq_info *info)
 {
 	u64 pidtid;
 
-	info->dsisr = cxl_p2n_read(ctx->afu, CXL_PSL_DSISR_An);
-	info->dar = cxl_p2n_read(ctx->afu, CXL_PSL_DAR_An);
-	info->dsr = cxl_p2n_read(ctx->afu, CXL_PSL_DSR_An);
-	pidtid = cxl_p2n_read(ctx->afu, CXL_PSL_PID_TID_An);
+	info->dsisr = cxl_p2n_read(afu, CXL_PSL_DSISR_An);
+	info->dar = cxl_p2n_read(afu, CXL_PSL_DAR_An);
+	info->dsr = cxl_p2n_read(afu, CXL_PSL_DSR_An);
+	pidtid = cxl_p2n_read(afu, CXL_PSL_PID_TID_An);
 	info->pid = pidtid >> 32;
 	info->tid = pidtid & 0xffffffff;
-	info->afu_err = cxl_p2n_read(ctx->afu, CXL_AFU_ERR_An);
-	info->errstat = cxl_p2n_read(ctx->afu, CXL_PSL_ErrStat_An);
+	info->afu_err = cxl_p2n_read(afu, CXL_AFU_ERR_An);
+	info->errstat = cxl_p2n_read(afu, CXL_PSL_ErrStat_An);
 
 	return 0;
 }