[Xen-changelog] [qemu-xen-4.5-testing] Without this the actual XSA-131 fix would cause the enable bit to not

[patchbot@xxxxxxx]

commit 751d20d7b12a31a435a3354e9d1cee9f2f0d8404
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Jun 9 16:32:24 2015 +0100
Commit:     Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
CommitDate: Tue Jun 9 16:32:24 2015 +0100

    Without this the actual XSA-131 fix would cause the enable bit to not
    get set anymore (due to the write back getting suppressed there based
    on the OR of emu_mask, ro_mask, and res_mask).
    
    Note that the fiddling with the enable bit shouldn't really be done by
    qemu, but making this work right (via libxc and the hypervisor) will
    require more extensive changes, which can be postponed until after the
    security issue got addressed.
    
    This is a preparatory patch for XSA-131.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
 hw/pass-through.c |   14 +++++++-------
 1 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/hw/pass-through.c b/hw/pass-through.c
index 2e18a21..8c63b8a 100644
--- a/hw/pass-through.c
+++ b/hw/pass-through.c
@@ -648,7 +648,7 @@ static struct pt_reg_info_tbl pt_emu_reg_msi_tbl[] = {
         .size       = 2,
         .init_val   = 0x0000,
         .ro_mask    = 0xFF8E,
-        .emu_mask   = 0x017F,
+        .emu_mask   = 0x017E,
         .init       = pt_msgctrl_reg_init,
         .u.w.read   = pt_word_reg_read,
         .u.w.write  = pt_msgctrl_reg_write,
@@ -3899,6 +3899,9 @@ static int pt_msgctrl_reg_write(struct pt_dev *ptdev,
 
     /* modify emulate register */
     writable_mask = reg->emu_mask & ~reg->ro_mask & valid_mask;
+    /* also emulate MSI_ENABLE bit for MSI-INTx translation */
+    if (ptdev->msi_trans_en)
+        writable_mask |= PCI_MSI_FLAGS_ENABLE & valid_mask;
     cfg_entry->data = PT_MERGE_VALUE(*value, cfg_entry->data, writable_mask);
     /* update the msi_info too */
     ptdev->msi->flags |= cfg_entry->data &
@@ -3907,6 +3910,9 @@ static int pt_msgctrl_reg_write(struct pt_dev *ptdev,
     /* create value for writing to I/O device register */
     val = *value;
     throughable_mask = ~reg->emu_mask & valid_mask;
+    /* don't pass through MSI_ENABLE bit for MSI-INTx translation */
+    if (ptdev->msi_trans_en)
+        throughable_mask &= ~PCI_MSI_FLAGS_ENABLE;
     *value = PT_MERGE_VALUE(*value, dev_value, throughable_mask);
 
     /* update MSI */
@@ -3950,12 +3956,6 @@ static int pt_msgctrl_reg_write(struct pt_dev *ptdev,
         }
     }
 
-    /* pass through MSI_ENABLE bit when no MSI-INTx translation */
-    if (!ptdev->msi_trans_en) {
-        *value &= ~PCI_MSI_FLAGS_ENABLE;
-        *value |= val & PCI_MSI_FLAGS_ENABLE;
-    }
-
     return 0;
 }
 
--
generated by git-patchbot for /home/xen/git/qemu-xen-4.5-testing.git

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