xive: Mask MMIO load/store to bad location FIR

For opencapi, the trigger page of an interrupt is mapped to user
space. The intent is to write the page to raise an interrupt but
there's nothing to prevent a user process from reading it, which has
the infortunate consequence of checkstopping the system.

Mask the FIR bit raised when an MMIO operation targets an invalid
location. It's the recommendation from recent documentation and
hostboot is expected to mask it at some point. In the meantime, let's
play it safe.

Signed-off-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/hw/xive.c b/hw/xive.c
index 271256b..998705e 100644
--- a/hw/xive.c
+++ b/hw/xive.c
@@ -1774,7 +1774,13 @@ static bool xive_config_init(struct xive *x)
 	/* Disable error reporting in the FIR for info errors
 	 * from the VC.
 	 */
-	xive_regw(x, CQ_FIRMASK_OR, 3ull);
+	xive_regw(x, CQ_FIRMASK_OR, CQ_FIR_VC_INFO_ERROR_0_1);
+
+	/* Mask CI Load and Store to bad location, as IPI trigger
+	 * pages may be mapped to user space, and a read on the
+	 * trigger page causes a checkstop
+	 */
+	xive_regw(x, CQ_FIRMASK_OR, CQ_FIR_PB_RCMDX_CI_ERR1);
 
 	return true;
 }