[v3,3/4] Revert "xen/balloon: Fix crash when ballooning on x86 32 bit PAE"
diff mbox series

Message ID 20200727091342.52325-4-roger.pau@citrix.com
State Superseded
Headers show
Series
  • xen/balloon: fixes for memory hotplug
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Commit Message

Roger Pau Monné July 27, 2020, 9:13 a.m. UTC
This reverts commit dfd74a1edfaba5864276a2859190a8d242d18952.

This has been fixed by commit dca4436d1cf9e0d237c which added the out
of bounds check to __add_memory, so that trying to add blocks past
MAX_PHYSMEM_BITS will fail.

Note the check in the Xen balloon driver was bogus anyway, as it
checked the start address of the resource, but it should instead test
the end address to assert the whole resource falls below
MAX_PHYSMEM_BITS.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
---
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: xen-devel@lists.xenproject.org
---
 drivers/xen/balloon.c | 14 --------------
 1 file changed, 14 deletions(-)

Comments

Jürgen Groß Aug. 3, 2020, 6:19 a.m. UTC | #1
On 27.07.20 11:13, Roger Pau Monne wrote:
> This reverts commit dfd74a1edfaba5864276a2859190a8d242d18952.
> 
> This has been fixed by commit dca4436d1cf9e0d237c which added the out
> of bounds check to __add_memory, so that trying to add blocks past
> MAX_PHYSMEM_BITS will fail.
> 
> Note the check in the Xen balloon driver was bogus anyway, as it
> checked the start address of the resource, but it should instead test
> the end address to assert the whole resource falls below
> MAX_PHYSMEM_BITS.
> 
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
> Reviewed-by: Juergen Gross <jgross@suse.com>

Pushed to: xen/tip.git for-linus-5.9


Juergen

Patch
diff mbox series

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 292413b27575..b1d8b028bf80 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -266,20 +266,6 @@  static struct resource *additional_memory_resource(phys_addr_t size)
 		return NULL;
 	}
 
-#ifdef CONFIG_SPARSEMEM
-	{
-		unsigned long limit = 1UL << (MAX_PHYSMEM_BITS - PAGE_SHIFT);
-		unsigned long pfn = res->start >> PAGE_SHIFT;
-
-		if (pfn > limit) {
-			pr_err("New System RAM resource outside addressable RAM (%lu > %lu)\n",
-			       pfn, limit);
-			release_memory_resource(res);
-			return NULL;
-		}
-	}
-#endif
-
 	return res;
 }