[Xen-devel] [PATCH v1 04/10] xen/pt: Use xen_host_pci_get_[byte, word, long] instead of xen_host_pci_get_long

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

Otherwise we get:

xen_pt_config_reg_init: Offset 0x0004 mismatch! Emulated=0x0000, 
host=0x2300017, syncing to 0x2300014.
xen_pt_config_reg_init: Error: Offset 0x0004:0x2300014 expands past register 
size(2)!

which is not surprising. We read the value as an 32-bit (from host),
then operate it as a 16-bit - and the remainder is left unchanged.

We end up writting the value as 16-bit (so 0014) to dev.config
(as we use proper xen_set_host_[byte,word,long] so we don't spill
to other registers) but in XenPTReg->data it is as 32-bit (0x2300014)!

It is harmless as the read/write functions end up using an size mask
and never modify the bits past 16-bit (reg->size is 2).

This patch fixes the warnings by reading the value using the
proper size.

Note that the check for size is still left in-case the developer
sets bits past the reg->size in the ->init routines.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
 hw/xen/xen_pt_config_init.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/hw/xen/xen_pt_config_init.c b/hw/xen/xen_pt_config_init.c
index 09309ba..e597993 100644
--- a/hw/xen/xen_pt_config_init.c
+++ b/hw/xen/xen_pt_config_init.c
@@ -1876,7 +1876,12 @@ static int xen_pt_config_reg_init(XenPCIPassthroughState 
*s,
         offset = reg_grp->base_offset + reg->offset;
         size_mask = 0xFFFFFFFF >> ((4 - reg->size) << 3);
 
-        rc = xen_host_pci_get_long(&s->real_device, offset, &val);
+        switch (reg->size) {
+        case 1: rc = xen_host_pci_get_byte(&s->real_device, offset, (uint8_t 
*)&val);break;
+        case 2: rc = xen_host_pci_get_word(&s->real_device, offset, (uint16_t 
*)&val);break;
+        case 4: rc = xen_host_pci_get_long(&s->real_device, offset, 
&val);break;
+        default: assert(1);
+        }
         if (rc) {
             /* Serious issues when we cannot read the host values! */
             g_free(reg_entry);
-- 
2.1.0


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