On 09/11/2017 19:55, Philippe Mathieu-Daudé wrote:
On 11/09/2017 01:38 PM, Cornelia Huck wrote:
On Tue, 7 Nov 2017 18:24:33 +0100
Pierre Morel <pmo...@linux.vnet.ibm.com> wrote:
There are two places where the same endianness conversion
is done.
Let's factor this out into a static function.
Signed-off-by: Pierre Morel <pmo...@linux.vnet.ibm.com>
Reviewed-by: Yi Min Zhao <zyi...@linux.vnet.ibm.com>
---
hw/s390x/s390-pci-inst.c | 58 ++++++++++++++++++++++++++----------------------
1 file changed, 32 insertions(+), 26 deletions(-)
diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c
index 8e088f3..8fcb02d 100644
--- a/hw/s390x/s390-pci-inst.c
+++ b/hw/s390x/s390-pci-inst.c
@@ -314,6 +314,35 @@ out:
return 0;
}
+/**
+ * This function swaps the data at ptr according from one
+ * endianness to the other.
+ * valid data in the uint64_t data field.
I'm not sure what that line is supposed to mean?
+ * @ptr: a pointer to a uint64_t data field
+ * @len: the length of the valid data, must be 1,2,4 or 8
+ */
+static int zpci_endian_swap(uint64_t *ptr, uint8_t len)
+{
+ uint64_t data = *ptr;
+ switch (len) {
+ case 1:
+ break;
+ case 2:
+ data = bswap16(data);
+ break;
+ case 4:
+ data = bswap32(data);
+ break;
+ case 8:
+ data = bswap64(data);
+ break;
+ default:
+ return -EINVAL;
+ }
+ *ptr = data;
+ return 0;
+}
This is usually care taken by memory::adjust_endianness() ...
We are here intercepting an instruction with the data in a register.
That is what troubles me, but I will take a deeper look.
I was expecting more code to use a similar pattern, but it seems
surprisingly uncommon.
Which ring a bell for latent bug?
This remind me of a similar issue on ppc:
http://lists.nongnu.org/archive/html/qemu-devel/2017-02/msg05121.html
...
http://lists.nongnu.org/archive/html/qemu-devel/2017-02/msg05666.html
Thanks for the pointers.
--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany
