diff mbox series

[for-5.0,v2,3/3] exec: Fix for qemu_ram_resize() callback

Message ID 20200403101827.30664-4-shameerali.kolothum.thodi@huawei.com (mailing list archive)
State New, archived
Headers show
Series acpi: Fixes for inconsistency in ACPI MR size during migration | expand

Commit Message

Shameerali Kolothum Thodi April 3, 2020, 10:18 a.m. UTC
From: David Hildenbrand <david@redhat.com>

Summarizing the issue:
1. Memory regions contain ram blocks with a different size,  if the
   size is  not properly aligned. While memory regions can have an
   unaligned size, ram blocks can't. This is true when creating
   resizable memory region with  an unaligned size.
2. When resizing a ram block/memory region, the size of the memory
   region  is set to the aligned size. The callback is called with
   the aligned size. The unaligned piece is lost.

Because of the above, if ACPI blob length modifications happens
after the initial virt_acpi_build() call, and the changed blob
length is within the PAGE size boundary, then the revised size
is not seen by the firmware on Guest reboot.

Hence make sure callback is called if memory region size is changed,
irrespective of aligned or not.

Signed-off-by: David Hildenbrand <david@redhat.com>
[Shameer: added commit log]
Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
---
Please find previous discussion here,
https://patchwork.kernel.org/patch/11432375/#23216751
---
 exec.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

Comments

Philippe Mathieu-Daudé April 3, 2020, 10:50 a.m. UTC | #1
On 4/3/20 12:18 PM, Shameer Kolothum wrote:
> From: David Hildenbrand <david@redhat.com>
> 
> Summarizing the issue:
> 1. Memory regions contain ram blocks with a different size,  if the
>     size is  not properly aligned. While memory regions can have an
>     unaligned size, ram blocks can't. This is true when creating
>     resizable memory region with  an unaligned size.
> 2. When resizing a ram block/memory region, the size of the memory
>     region  is set to the aligned size. The callback is called with
>     the aligned size. The unaligned piece is lost.
> 
> Because of the above, if ACPI blob length modifications happens
> after the initial virt_acpi_build() call, and the changed blob
> length is within the PAGE size boundary, then the revised size
> is not seen by the firmware on Guest reboot.
> 
> Hence make sure callback is called if memory region size is changed,
> irrespective of aligned or not.
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>
> [Shameer: added commit log]
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> Reviewed-by: Igor Mammedov <imammedo@redhat.com>

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> ---
> Please find previous discussion here,
> https://patchwork.kernel.org/patch/11432375/#23216751
> ---
>   exec.c | 16 ++++++++++++++--
>   1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/exec.c b/exec.c
> index de9d949902..2874bb5088 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -2074,11 +2074,23 @@ static int memory_try_enable_merging(void *addr, size_t len)
>    */
>   int qemu_ram_resize(RAMBlock *block, ram_addr_t newsize, Error **errp)
>   {
> +    const ram_addr_t unaligned_size = newsize;
> +
>       assert(block);
>   
>       newsize = HOST_PAGE_ALIGN(newsize);
>   
>       if (block->used_length == newsize) {
> +        /*
> +         * We don't have to resize the ram block (which only knows aligned
> +         * sizes), however, we have to notify if the unaligned size changed.
> +         */
> +        if (unaligned_size != memory_region_size(block->mr)) {
> +            memory_region_set_size(block->mr, unaligned_size);
> +            if (block->resized) {
> +                block->resized(block->idstr, unaligned_size, block->host);
> +            }
> +        }
>           return 0;
>       }
>   
> @@ -2102,9 +2114,9 @@ int qemu_ram_resize(RAMBlock *block, ram_addr_t newsize, Error **errp)
>       block->used_length = newsize;
>       cpu_physical_memory_set_dirty_range(block->offset, block->used_length,
>                                           DIRTY_CLIENTS_ALL);
> -    memory_region_set_size(block->mr, newsize);
> +    memory_region_set_size(block->mr, unaligned_size);
>       if (block->resized) {
> -        block->resized(block->idstr, newsize, block->host);
> +        block->resized(block->idstr, unaligned_size, block->host);
>       }
>       return 0;
>   }
>
diff mbox series

Patch

diff --git a/exec.c b/exec.c
index de9d949902..2874bb5088 100644
--- a/exec.c
+++ b/exec.c
@@ -2074,11 +2074,23 @@  static int memory_try_enable_merging(void *addr, size_t len)
  */
 int qemu_ram_resize(RAMBlock *block, ram_addr_t newsize, Error **errp)
 {
+    const ram_addr_t unaligned_size = newsize;
+
     assert(block);
 
     newsize = HOST_PAGE_ALIGN(newsize);
 
     if (block->used_length == newsize) {
+        /*
+         * We don't have to resize the ram block (which only knows aligned
+         * sizes), however, we have to notify if the unaligned size changed.
+         */
+        if (unaligned_size != memory_region_size(block->mr)) {
+            memory_region_set_size(block->mr, unaligned_size);
+            if (block->resized) {
+                block->resized(block->idstr, unaligned_size, block->host);
+            }
+        }
         return 0;
     }
 
@@ -2102,9 +2114,9 @@  int qemu_ram_resize(RAMBlock *block, ram_addr_t newsize, Error **errp)
     block->used_length = newsize;
     cpu_physical_memory_set_dirty_range(block->offset, block->used_length,
                                         DIRTY_CLIENTS_ALL);
-    memory_region_set_size(block->mr, newsize);
+    memory_region_set_size(block->mr, unaligned_size);
     if (block->resized) {
-        block->resized(block->idstr, newsize, block->host);
+        block->resized(block->idstr, unaligned_size, block->host);
     }
     return 0;
 }