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authorJan Beulich <jbeulich@suse.com>2015-06-02 15:07:01 +0000
committerStefano Stabellini <stefano.stabellini@eu.citrix.com>2015-06-02 15:07:01 +0000
commitd1d35cf4ffb6a60a356193397919e83306d0bb74 (patch)
tree7fb4adf2f8ad149976b465eac234a10d3d2b38f9
parentb38ec5ee7a581776bbce0bdaecb397632c3c4791 (diff)
xen/MSI: don't open-code pass-through of enable bit modifications
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@suse.com> Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
-rw-r--r--hw/xen/xen_pt_config_init.c10
1 files changed, 2 insertions, 8 deletions
diff --git a/hw/xen/xen_pt_config_init.c b/hw/xen/xen_pt_config_init.c
index 68b8f22648..436d0fdc6a 100644
--- a/hw/xen/xen_pt_config_init.c
+++ b/hw/xen/xen_pt_config_init.c
@@ -1053,7 +1053,6 @@ static int xen_pt_msgctrl_reg_write(XenPCIPassthroughState *s,
XenPTMSI *msi = s->msi;
uint16_t writable_mask = 0;
uint16_t throughable_mask = 0;
- uint16_t raw_val;
/* Currently no support for multi-vector */
if (*val & PCI_MSI_FLAGS_QSIZE) {
@@ -1066,12 +1065,11 @@ static int xen_pt_msgctrl_reg_write(XenPCIPassthroughState *s,
msi->flags |= cfg_entry->data & ~PCI_MSI_FLAGS_ENABLE;
/* create value for writing to I/O device register */
- raw_val = *val;
throughable_mask = ~reg->emu_mask & valid_mask;
*val = XEN_PT_MERGE_VALUE(*val, dev_value, throughable_mask);
/* update MSI */
- if (raw_val & PCI_MSI_FLAGS_ENABLE) {
+ if (*val & PCI_MSI_FLAGS_ENABLE) {
/* setup MSI pirq for the first time */
if (!msi->initialized) {
/* Init physical one */
@@ -1099,10 +1097,6 @@ static int xen_pt_msgctrl_reg_write(XenPCIPassthroughState *s,
xen_pt_msi_disable(s);
}
- /* pass through MSI_ENABLE bit */
- *val &= ~PCI_MSI_FLAGS_ENABLE;
- *val |= raw_val & PCI_MSI_FLAGS_ENABLE;
-
return 0;
}
@@ -1301,7 +1295,7 @@ static XenPTRegInfo xen_pt_emu_reg_msi[] = {
.size = 2,
.init_val = 0x0000,
.ro_mask = 0xFF8E,
- .emu_mask = 0x017F,
+ .emu_mask = 0x017E,
.init = xen_pt_msgctrl_reg_init,
.u.w.read = xen_pt_word_reg_read,
.u.w.write = xen_pt_msgctrl_reg_write,