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From:   Nicholas Miehlbradt <nicholas@linux.ibm.com>
To:     glider@google.com, elver@google.com, dvyukov@google.com,
        akpm@linux-foundation.org, mpe@ellerman.id.au, npiggin@gmail.com,
        christophe.leroy@csgroup.eu
Cc:     linux-mm@kvack.org, kasan-dev@googlegroups.com, iii@linux.ibm.com,
        linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        Nicholas Miehlbradt <nicholas@linux.ibm.com>
Subject: [PATCH 05/13] powerpc: Unpoison buffers populated by hcalls
Date:   Thu, 14 Dec 2023 05:55:31 +0000
Message-Id: <20231214055539.9420-6-nicholas@linux.ibm.com>
In-Reply-To: <20231214055539.9420-1-nicholas@linux.ibm.com>
References: <20231214055539.9420-1-nicholas@linux.ibm.com>
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plpar_hcall provides to the hypervisor a buffer where return data should be
placed. The hypervisor initializes the buffers which is not visible to
KMSAN so unpoison them manually.

Signed-off-by: Nicholas Miehlbradt <nicholas@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/hvconsole.c | 2 ++
 arch/powerpc/sysdev/xive/spapr.c           | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/hvconsole.c b/arch/powerpc/platforms/pseries/hvconsole.c
index 1ac52963e08b..7ad66acd5db8 100644
--- a/arch/powerpc/platforms/pseries/hvconsole.c
+++ b/arch/powerpc/platforms/pseries/hvconsole.c
@@ -13,6 +13,7 @@
 #include <linux/kernel.h>
 #include <linux/export.h>
 #include <linux/errno.h>
+#include <linux/kmsan-checks.h>
 #include <asm/hvcall.h>
 #include <asm/hvconsole.h>
 #include <asm/plpar_wrappers.h>
@@ -32,6 +33,7 @@ int hvc_get_chars(uint32_t vtermno, char *buf, int count)
 	unsigned long *lbuf = (unsigned long *)buf;
 
 	ret = plpar_hcall(H_GET_TERM_CHAR, retbuf, vtermno);
+	kmsan_unpoison_memory(retbuf, sizeof(retbuf));
 	lbuf[0] = be64_to_cpu(retbuf[1]);
 	lbuf[1] = be64_to_cpu(retbuf[2]);
 
diff --git a/arch/powerpc/sysdev/xive/spapr.c b/arch/powerpc/sysdev/xive/spapr.c
index e45419264391..a9f48a336e4d 100644
--- a/arch/powerpc/sysdev/xive/spapr.c
+++ b/arch/powerpc/sysdev/xive/spapr.c
@@ -20,6 +20,7 @@
 #include <linux/mm.h>
 #include <linux/delay.h>
 #include <linux/libfdt.h>
+#include <linux/kmsan-checks.h>
 
 #include <asm/machdep.h>
 #include <asm/prom.h>
@@ -191,6 +192,8 @@ static long plpar_int_get_source_info(unsigned long flags,
 		return rc;
 	}
 
+	kmsan_unpoison_memory(retbuf, sizeof(retbuf));
+
 	*src_flags = retbuf[0];
 	*eoi_page  = retbuf[1];
 	*trig_page = retbuf[2];
-- 
2.40.1