xen/pt: mark reserved bits in PCI config space fields

The adjustments are solely to make the subsequent patches work right
(and hence make the patch set consistent), namely if permissive mode
(introduced by the last patch) gets used (as both reserved registers
and reserved fields must be similarly protected from guest access in
default mode, but the guest should be allowed access to them in
permissive mode).

This is a preparatory patch for XSA-131.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/hw/pass-through.c
+++ b/hw/pass-through.c
@@ -283,7 +283,7 @@ static struct pt_reg_info_tbl pt_emu_reg
         .offset     = PCI_COMMAND,
         .size       = 2,
         .init_val   = 0x0000,
-        .ro_mask    = 0xF880,
+        .res_mask   = 0xF880,
         .emu_mask   = 0x0743,
         .init       = pt_common_reg_init,
         .u.w.read   = pt_word_reg_read,
@@ -310,7 +310,8 @@ static struct pt_reg_info_tbl pt_emu_reg
         .offset     = PCI_STATUS,
         .size       = 2,
         .init_val   = 0x0000,
-        .ro_mask    = 0x06FF,
+        .res_mask   = 0x0007,
+        .ro_mask    = 0x06F8,
         .emu_mask   = 0x0010,
         .init       = pt_status_reg_init,
         .u.w.read   = pt_word_reg_read,
@@ -496,7 +497,8 @@ static struct pt_reg_info_tbl pt_emu_reg
         .offset     = PCI_PM_CTRL,
         .size       = 2,
         .init_val   = 0x0008,
-        .ro_mask    = 0xE1FC,
+        .res_mask   = 0x00F0,
+        .ro_mask    = 0xE10C,
         .emu_mask   = 0x8100,
         .init       = pt_pmcsr_reg_init,
         .u.w.read   = pt_word_reg_read,
@@ -508,7 +510,8 @@ static struct pt_reg_info_tbl pt_emu_reg
         .offset     = PCI_PM_CTRL,
         .size       = 2,
         .init_val   = 0x0008,
-        .ro_mask    = 0xE1FC,
+        .res_mask   = 0x00F0,
+        .ro_mask    = 0xE10C,
         .emu_mask   = 0x810B,
         .init       = pt_pmcsr_reg_init,
         .u.w.read   = pt_word_reg_read,
@@ -656,7 +659,8 @@ static struct pt_reg_info_tbl pt_emu_reg
         .offset     = PCI_MSI_FLAGS, // 2
         .size       = 2,
         .init_val   = 0x0000,
-        .ro_mask    = 0xFF8E,
+        .res_mask   = 0xFE00,
+        .ro_mask    = 0x018E,
         .emu_mask   = 0x017E,
         .init       = pt_msgctrl_reg_init,
         .u.w.read   = pt_word_reg_read,
@@ -779,7 +783,8 @@ static struct pt_reg_info_tbl pt_emu_reg
         .offset     = PCI_MSI_FLAGS, // 2
         .size       = 2,
         .init_val   = 0x0000,
-        .ro_mask    = 0x3FFF,
+        .res_mask   = 0x3800,
+        .ro_mask    = 0x07FF,
         .emu_mask   = 0x0000,
         .init       = pt_msixctrl_reg_init,
         .u.w.read   = pt_word_reg_read,
--- a/hw/pass-through.h
+++ b/hw/pass-through.h
@@ -376,6 +376,8 @@ struct pt_reg_info_tbl {
     uint32_t size;
     /* reg initial value */
     uint32_t init_val;
+    /* reg reserved field mask (ON:reserved, OFF:defined) */
+    uint32_t res_mask;
     /* reg read only field mask (ON:RO/ROS, OFF:other) */
     uint32_t ro_mask;
     /* reg emulate field mask (ON:emu, OFF:passthrough) */