[PATCH AUTOSEL 4.14 9/9] xen/xenbus: Fix granting of vmalloc'd memory

Sasha Levin
2020-08-31T15:32:21Z

From: Simon Leiner <simon@leiner.me>

[ Upstream commit d742db70033c745e410523e00522ee0cfe2aa416 ]

On some architectures (like ARM), virt_to_gfn cannot be used for
vmalloc'd memory because of its reliance on virt_to_phys. This patch
introduces a check for vmalloc'd addresses and obtains the PFN using
vmalloc_to_pfn in that case.

Signed-off-by: Simon Leiner <simon@leiner.me>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20200825093153.35500-1-simon@leiner.me
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/xen/xenbus/xenbus_client.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index e94a61eaeceb0..f7b553faadb10 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -365,8 +365,14 @@ int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
int i, j;

for (i = 0; i < nr_pages; i++) {
- err = gnttab_grant_foreign_access(dev->otherend_id,
- virt_to_gfn(vaddr), 0);
+ unsigned long gfn;
+
+ if (is_vmalloc_addr(vaddr))
+ gfn = pfn_to_gfn(vmalloc_to_pfn(vaddr));
+ else
+ gfn = virt_to_gfn(vaddr);
+
+ err = gnttab_grant_foreign_access(dev->otherend_id, gfn, 0);
if (err < 0) {
xenbus_dev_fatal(dev, err,
"granting access to ring page");
--
2.25.1