From: Stefano Stabellini <sstabellini@kernel.org>
To: xen-devel@lists.xenproject.org
Cc: sstabellini@kernel.org, hch@lst.de, linux-kernel@vger.kernel.org,
Stefano Stabellini <stefano.stabellini@xilinx.com>,
boris.ostrovsky@oracle.com, jgross@suse.com
Subject: [PATCH 2/2] xen/swiotlb: check if the swiotlb has already been initialized
Date: Tue, 11 May 2021 10:41:42 -0700 [thread overview]
Message-ID: <20210511174142.12742-2-sstabellini@kernel.org> (raw)
From: Stefano Stabellini <stefano.stabellini@xilinx.com>
xen_swiotlb_init calls swiotlb_late_init_with_tbl, which fails with
-ENOMEM if the swiotlb has already been initialized.
Add an explicit check io_tlb_default_mem != NULL at the beginning of
xen_swiotlb_init. If the swiotlb is already initialized print a warning
and return -EEXIST.
On x86, the error propagates.
On ARM, we don't actually need a special swiotlb buffer (yet), any
buffer would do. So ignore the error and continue.
CC: boris.ostrovsky@oracle.com
CC: jgross@suse.com
Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
---
arch/arm/xen/mm.c | 8 +++++++-
drivers/xen/swiotlb-xen.c | 5 +++++
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
index 223b1151fd7d..a7e54a087b80 100644
--- a/arch/arm/xen/mm.c
+++ b/arch/arm/xen/mm.c
@@ -138,9 +138,15 @@ void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
static int __init xen_mm_init(void)
{
struct gnttab_cache_flush cflush;
+ int rc;
+
if (!xen_swiotlb_detect())
return 0;
- xen_swiotlb_init();
+
+ rc = xen_swiotlb_init();
+ /* we can work with the default swiotlb */
+ if (rc < 0 && rc != -EEXIST)
+ return rc;
cflush.op = 0;
cflush.a.dev_bus_addr = 0;
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 4c89afc0df62..6412d59ce7f8 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -164,6 +164,11 @@ int __ref xen_swiotlb_init(void)
int rc = -ENOMEM;
char *start;
+ if (io_tlb_default_mem != NULL) {
+ printk(KERN_WARNING "Xen-SWIOTLB: swiotlb buffer already initialized\n");
+ return -EEXIST;
+ }
+
retry:
m_ret = XEN_SWIOTLB_ENOMEM;
order = get_order(bytes);
--
2.17.1
next reply other threads:[~2021-05-11 17:42 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-11 17:41 Stefano Stabellini [this message]
2021-05-11 23:37 ` [PATCH 2/2] xen/swiotlb: check if the swiotlb has already been initialized Boris Ostrovsky
2021-05-12 20:10 ` Stefano Stabellini
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