vgabios: Check that the PCI BDF passed in is valid before using.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

5 files changed, 20 insertions, 10 deletions

diff --git a/vgasrc/bochsvga.c b/vgasrc/bochsvga.c
index 82629b9..cbd0b41 100644
--- a/vgasrc/bochsvga.c
+++ b/vgasrc/bochsvga.c
@@ -123,12 +123,11 @@ bochsvga_init(void)
 
     dispi_write(VBE_DISPI_INDEX_ID, VBE_DISPI_ID5);
 
-    u32 lfb_addr;
-    if (CONFIG_VGA_PCI)
-        lfb_addr = (pci_config_readl(GET_GLOBAL(VgaBDF), PCI_BASE_ADDRESS_0)
+    u32 lfb_addr = VBE_DISPI_LFB_PHYSICAL_ADDRESS;
+    int bdf = GET_GLOBAL(VgaBDF);
+    if (CONFIG_VGA_PCI && bdf >= 0)
+        lfb_addr = (pci_config_readl(bdf, PCI_BASE_ADDRESS_0)
                     & PCI_BASE_ADDRESS_MEM_MASK);
-    else
-        lfb_addr = VBE_DISPI_LFB_PHYSICAL_ADDRESS;
 
     SET_VGA(VBE_framebuffer, lfb_addr);
     u16 totalmem = dispi_read(VBE_DISPI_INDEX_VIDEO_MEMORY_64K);
diff --git a/vgasrc/clext.c b/vgasrc/clext.c
index f08294a..5468db3 100644
--- a/vgasrc/clext.c
+++ b/vgasrc/clext.c
@@ -737,8 +737,9 @@ clext_init(void)
     dprintf(1, "cirrus init 2\n");
 
     u32 lfb_addr = 0;
-    if (CONFIG_VGA_PCI)
-        lfb_addr = (pci_config_readl(GET_GLOBAL(VgaBDF), PCI_BASE_ADDRESS_0)
+    int bdf = GET_GLOBAL(VgaBDF);
+    if (CONFIG_VGA_PCI && bdf >= 0)
+        lfb_addr = (pci_config_readl(bdf, PCI_BASE_ADDRESS_0)
                     & PCI_BASE_ADDRESS_MEM_MASK);
     SET_VGA(VBE_framebuffer, lfb_addr);
     u16 totalmem = cirrus_get_memsize();
diff --git a/vgasrc/geodevga.c b/vgasrc/geodevga.c
index ce754a5..5c6caf0 100644
--- a/vgasrc/geodevga.c
+++ b/vgasrc/geodevga.c
@@ -363,6 +363,9 @@ int geodevga_init(void)
             stdvga_override_crtc(i, crtc);
     }
 
+    if (GET_GLOBAL(VgaBDF) < 0)
+        // Device should be at 00:01.1
+        SET_VGA(VgaBDF, pci_to_bdf(0, 1, 1));
     ret |= vp_setup();
     ret |= dc_setup();
 
diff --git a/vgasrc/vgabios.c b/vgasrc/vgabios.c
index 449f3c4..5ce7c0c 100644
--- a/vgasrc/vgabios.c
+++ b/vgasrc/vgabios.c
@@ -20,6 +20,8 @@
 #include "stdvga.h" // stdvga_set_cursor_shape
 #include "clext.h" // clext_1012
 #include "vgahw.h" // vgahw_set_mode
+#include "pci.h" // pci_config_readw
+#include "pci_regs.h" // PCI_VENDOR_ID
 
 // XXX
 #define DEBUG_VGA_POST 1
@@ -1226,14 +1228,19 @@ init_bios_area(void)
     SET_BDA(video_msr, 0x09);
 }
 
-u16 VgaBDF VAR16;
+int VgaBDF VAR16 = -1;
 
 void VISIBLE16
 vga_post(struct bregs *regs)
 {
     debug_enter(regs, DEBUG_VGA_POST);
 
-    SET_VGA(VgaBDF, regs->ax);
+    if (CONFIG_VGA_PCI) {
+        u16 bdf = regs->ax;
+        if (pci_config_readw(bdf, PCI_VENDOR_ID) == CONFIG_VGA_VID
+            && pci_config_readw(bdf, PCI_DEVICE_ID) == CONFIG_VGA_DID)
+            SET_VGA(VgaBDF, bdf);
+    }
 
     int ret = vgahw_init();
     if (ret) {
diff --git a/vgasrc/vgabios.h b/vgasrc/vgabios.h
index 403e7ce..6895a39 100644
--- a/vgasrc/vgabios.h
+++ b/vgasrc/vgabios.h
@@ -73,7 +73,7 @@ extern u8 vgafont14alt[];
 extern u8 vgafont16alt[];
 
 // vgabios.c
-extern u16 VgaBDF;
+extern int VgaBDF;
 #define SET_VGA(var, val) SET_FARVAR(get_global_seg(), (var), (val))
 struct carattr {
     u8 car, attr, use_attr;