Blame SOURCES/0020-BZ1653590-Require-at-least-64kiB-pages-for-downstrea.patch

ddf19c
From 148e9e80a3a430615b552075082fad22d007d851 Mon Sep 17 00:00:00 2001
ddf19c
From: David Gibson <dgibson@redhat.com>
ddf19c
Date: Wed, 6 Feb 2019 03:58:56 +0000
ddf19c
Subject: BZ1653590: Require at least 64kiB pages for downstream guests & hosts
ddf19c
ddf19c
RH-Author: David Gibson <dgibson@redhat.com>
ddf19c
Message-id: <20190206035856.19058-1-dgibson@redhat.com>
ddf19c
Patchwork-id: 84246
ddf19c
O-Subject: [RHELAV-8.0/rhel qemu-kvm PATCH] BZ1653590: Require at least 64kiB pages for downstream guests & hosts
ddf19c
Bugzilla: 1653590
ddf19c
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
ddf19c
RH-Acked-by: Serhii Popovych <spopovyc@redhat.com>
ddf19c
RH-Acked-by: Thomas Huth <thuth@redhat.com>
ddf19c
ddf19c
Most current POWER guests require 64kiB page support, so that's the default
ddf19c
for the cap-hpt-max-pagesize option in qemu which limits available guest
ddf19c
page sizes.  We warn if the value is set smaller than that, but don't
ddf19c
outright fail upstream, because we need to allow for the possibility of
ddf19c
guest (and/or host) kernels configured for 4kiB page sizes.
ddf19c
ddf19c
Downstream, however, we simply don't support 4kiB pagesize configured
ddf19c
kernels in guest or host, so we can have qemu simply error out in this
ddf19c
situation.
ddf19c
ddf19c
Testing: Attempted to start a guest with cap-hpt-max-page-size=4k and verified
ddf19c
         it failed immediately with a qemu error
ddf19c
ddf19c
Signed-off-by: David Gibson <dgibson@redhat.com>
ddf19c
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
ddf19c
---
ddf19c
 hw/ppc/spapr_caps.c | 7 +++++++
ddf19c
 1 file changed, 7 insertions(+)
ddf19c
ddf19c
diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c
ddf19c
index 481dfd2a27..805f38533e 100644
ddf19c
--- a/hw/ppc/spapr_caps.c
ddf19c
+++ b/hw/ppc/spapr_caps.c
ddf19c
@@ -351,12 +351,19 @@ void spapr_check_pagesize(SpaprMachineState *spapr, hwaddr pagesize,
ddf19c
 static void cap_hpt_maxpagesize_apply(SpaprMachineState *spapr,
ddf19c
                                       uint8_t val, Error **errp)
ddf19c
 {
ddf19c
+#if 0 /* disabled for RHEL */
ddf19c
     if (val < 12) {
ddf19c
         error_setg(errp, "Require at least 4kiB hpt-max-page-size");
ddf19c
         return;
ddf19c
     } else if (val < 16) {
ddf19c
         warn_report("Many guests require at least 64kiB hpt-max-page-size");
ddf19c
     }
ddf19c
+#else /* Only page sizes >=64kiB supported for RHEL */
ddf19c
+    if (val < 16) {
ddf19c
+        error_setg(errp, "Require at least 64kiB hpt-max-page-size");
ddf19c
+        return;
ddf19c
+    }
ddf19c
+#endif
ddf19c
 
ddf19c
     spapr_check_pagesize(spapr, qemu_minrampagesize(), errp);
ddf19c
 }
ddf19c
-- 
ddf19c
2.21.0
ddf19c