[Xen-changelog] [qemu-xen-unstable] passthough: add no_wb option for pci conf write

[Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>]

commit e2b98415256cb264bc25e6df539ec0dc9d1b85b0
Author: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Date:   Fri Nov 6 18:11:50 2009 +0000

    passthough: add no_wb option for pci conf write
    
    Current pt_pci_write_config always writes back to real pci conf
    space. However, in the case of MSI address and data registers,
    if guest changes the affinity of the interrupt, stale data will
    be written to these registers. This is particularly a problem
    if Xen uses per-CPU vector, where the interrupt in question fails
    to work. This patch fixes this by adding an option to disable the
    write back of certain controls.
    
    Signed-off-by: Qing He <qing.he@xxxxxxxxx>
---
 hw/pass-through.c |   12 +++++++++---
 hw/pass-through.h |    2 ++
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/hw/pass-through.c b/hw/pass-through.c
index cdf0f31..b125d72 100644
--- a/hw/pass-through.c
+++ b/hw/pass-through.c
@@ -628,6 +628,7 @@ static struct pt_reg_info_tbl pt_emu_reg_msi_tbl[] = {
         .init_val   = 0x00000000,
         .ro_mask    = 0x00000003,
         .emu_mask   = 0xFFFFFFFF,
+        .no_wb      = 1,
         .init       = pt_common_reg_init,
         .u.dw.read  = pt_long_reg_read,
         .u.dw.write = pt_msgaddr32_reg_write,
@@ -640,6 +641,7 @@ static struct pt_reg_info_tbl pt_emu_reg_msi_tbl[] = {
         .init_val   = 0x00000000,
         .ro_mask    = 0x00000000,
         .emu_mask   = 0xFFFFFFFF,
+        .no_wb      = 1,
         .init       = pt_msgaddr64_reg_init,
         .u.dw.read  = pt_long_reg_read,
         .u.dw.write = pt_msgaddr64_reg_write,
@@ -652,6 +654,7 @@ static struct pt_reg_info_tbl pt_emu_reg_msi_tbl[] = {
         .init_val   = 0x0000,
         .ro_mask    = 0x0000,
         .emu_mask   = 0xFFFF,
+        .no_wb      = 1,
         .init       = pt_msgdata_reg_init,
         .u.w.read   = pt_word_reg_read,
         .u.w.write  = pt_msgdata_reg_write,
@@ -664,6 +667,7 @@ static struct pt_reg_info_tbl pt_emu_reg_msi_tbl[] = {
         .init_val   = 0x0000,
         .ro_mask    = 0x0000,
         .emu_mask   = 0xFFFF,
+        .no_wb      = 1,
         .init       = pt_msgdata_reg_init,
         .u.w.read   = pt_word_reg_read,
         .u.w.write  = pt_msgdata_reg_write,
@@ -1552,10 +1556,12 @@ static void pt_pci_write_config(PCIDevice *d, uint32_t 
address, uint32_t val,
     val >>= ((address & 3) << 3);
 
 out:
-    ret = pci_write_block(pci_dev, address, (uint8_t *)&val, len);
+    if (!reg->no_wb) {
+        ret = pci_write_block(pci_dev, address, (uint8_t *)&val, len);
 
-    if (!ret)
-        PT_LOG("Error: pci_write_block failed. return value[%d].\n", ret);
+        if (!ret)
+            PT_LOG("Error: pci_write_block failed. return value[%d].\n", ret);
+    }
 
     if (pm_state != NULL && pm_state->flags & PT_FLAG_TRANSITING)
         /* set QEMUTimer */
diff --git a/hw/pass-through.h b/hw/pass-through.h
index 324df5b..dc06a4f 100644
--- a/hw/pass-through.h
+++ b/hw/pass-through.h
@@ -365,6 +365,8 @@ struct pt_reg_info_tbl {
     uint32_t ro_mask;
     /* reg emulate field mask (ON:emu, OFF:passthrough) */
     uint32_t emu_mask;
+    /* no write back allowed */
+    uint32_t no_wb;
     /* emul reg initialize method */
     conf_reg_init init;
     union {
--
generated by git-patchbot for /home/xen/git/qemu-xen-unstable.git

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