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[Xen-devel] [PATCH] firmware/vgabios: Port PCI based VBE LFB discovery method from QEMU fork



QEMU-traditional implements non-standard VBE registers for getting LFB
physical address from inside of VGA BIOS code. QEMU doesn't have
those registers implemented and returns 0 when an HVM guest is trying to
access them from the existing ROMBIOS code. This eventually leads to
a triple fault inside a guest which happened to use ROMBIOS instead of
SeaBIOS when in stdvga mode.

QEMU maintains its own fork of VGA BIOS where the VBE LFB discovery is
implemented through a regular PCI BAR reading. In order to support that
we need to build a PCI compliant VGA BIOS version for stdvga and include
it into ROMBIOS instead of the old one.

Signed-off-by: Igor Druzhinin <igor.druzhinin@xxxxxxxxxx>
---
CC: Jan Beulich <jbeulich@xxxxxxxx>
CC: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CC: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
CC: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 tools/firmware/hvmloader/Makefile |  2 +-
 tools/firmware/vgabios/Makefile   | 29 +++++++++++++++--
 tools/firmware/vgabios/vbe.c      |  9 ++++++
 tools/firmware/vgabios/vgabios.c  | 68 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 105 insertions(+), 3 deletions(-)

diff --git a/tools/firmware/hvmloader/Makefile 
b/tools/firmware/hvmloader/Makefile
index 80d7b44..5f6eacd 100644
--- a/tools/firmware/hvmloader/Makefile
+++ b/tools/firmware/hvmloader/Makefile
@@ -45,7 +45,7 @@ CIRRUSVGA_DEBUG ?= n
 ROMBIOS_DIR := ../rombios
 
 ifeq ($(CONFIG_ROMBIOS),y)
-STDVGA_ROM    := ../vgabios/VGABIOS-lgpl-latest.bin
+STDVGA_ROM    := ../vgabios/VGABIOS-lgpl-latest.stdvga.bin
 ifeq ($(CIRRUSVGA_DEBUG),y)
 CIRRUSVGA_ROM := ../vgabios/VGABIOS-lgpl-latest.cirrus.debug.bin
 else
diff --git a/tools/firmware/vgabios/Makefile b/tools/firmware/vgabios/Makefile
index 3284812..0f4026e 100644
--- a/tools/firmware/vgabios/Makefile
+++ b/tools/firmware/vgabios/Makefile
@@ -11,7 +11,7 @@ RELVERS = `pwd | sed "s-.*/--" | sed "s/vgabios//" | sed 
"s/-//"`
 VGABIOS_DATE = "-DVGABIOS_DATE=\"$(VGABIOS_REL_DATE)\""
 
 .PHONY: all
-all: bios cirrus-bios
+all: bios cirrus-bios stdvga-bios
 
 .PHONY: bios
 bios: biossums vgabios.bin vgabios.debug.bin 
@@ -19,6 +19,9 @@ bios: biossums vgabios.bin vgabios.debug.bin
 .PHONY: cirrus-bios
 cirrus-bios: vgabios-cirrus.bin vgabios-cirrus.debug.bin
 
+.PHONY: stdvga-bios
+stdvga-bios: vgabios-stdvga.bin vgabios-stdvga.debug.bin
+
 .PHONY: clean
 clean:
        rm -f  biossums vbetables-gen vbetables.h *.o *.s *.ld86 \
@@ -30,13 +33,15 @@ distclean: clean
 
 .PHONY: release
 release: 
-       VGABIOS_VERS=\"-DVGABIOS_VERS=\\\"$(RELVERS)\\\"\" make bios cirrus-bios
+       VGABIOS_VERS=\"-DVGABIOS_VERS=\\\"$(RELVERS)\\\"\" make bios 
cirrus-bios stdvga-bios
        /bin/rm -f  *.o *.s *.ld86 \
           temp.awk.* vgabios.*.orig _vgabios_.*.c core *.bak .#*
        cp VGABIOS-lgpl-latest.bin ../$(RELEASE).bin
        cp VGABIOS-lgpl-latest.debug.bin ../$(RELEASE).debug.bin
        cp VGABIOS-lgpl-latest.cirrus.bin ../$(RELEASE).cirrus.bin
        cp VGABIOS-lgpl-latest.cirrus.debug.bin ../$(RELEASE).cirrus.debug.bin
+       cp VGABIOS-lgpl-latest.stdvga.bin ../$(RELEASE).stdvga.bin
+       cp VGABIOS-lgpl-latest.stdvga.debug.bin ../$(RELEASE).stdvga.debug.bin
        tar czvf ../$(RELEASE).tgz --exclude CVS -C .. $(RELEASE)/
 
 vgabios.bin: biossums vgabios.c vgabios.h vgafonts.h vgatables.h vbe.h vbe.c 
vbetables.h
@@ -59,6 +64,26 @@ vgabios.debug.bin: biossums vgabios.c vgabios.h vgafonts.h 
vgatables.h vbe.h vbe
        ./biossums VGABIOS-lgpl-latest.debug.bin
        ls -l VGABIOS-lgpl-latest.debug.bin
 
+vgabios-stdvga.bin: biossums vgabios.c vgabios.h vgafonts.h vgatables.h vbe.h 
vbe.c vbetables.h
+       $(GCC) -E -P vgabios.c $(VGABIOS_VERS) -DVBE -DPCIBIOS -DPCI_VID=0x1234 
-DPCI_DID=0x1111 $(VGABIOS_DATE) > _vgabios-stdvga_.c
+       $(BCC) -o vgabios-stdvga.s -C-c -D__i86__ -S -0 _vgabios-stdvga_.c
+       sed -e 's/^\.text//' -e 's/^\.data//' vgabios-stdvga.s > 
_vgabios-stdvga_.s
+       $(AS86) _vgabios-stdvga_.s -b vgabios-stdvga.bin -u -w- -g -0 -j -O -l 
vgabios-stdvga.txt
+       rm -f _vgabios-stdvga_.s _vgabios-stdvga_.c vgabios-stdvga.s
+       cp vgabios-stdvga.bin VGABIOS-lgpl-latest.stdvga.bin
+       ./biossums VGABIOS-lgpl-latest.stdvga.bin
+       ls -l VGABIOS-lgpl-latest.stdvga.bin
+
+vgabios-stdvga.debug.bin: biossums vgabios.c vgabios.h vgafonts.h vgatables.h 
vbe.h vbe.c vbetables.h
+       $(GCC) -E -P vgabios.c $(VGABIOS_VERS) -DVBE -DPCIBIOS -DPCI_VID=0x1234 
-DPCI_DID=0x1111 -DDEBUG $(VGABIOS_DATE) > _vgabios-stdvga-debug_.c
+       $(BCC) -o vgabios-stdvga-debug.s -C-c -D__i86__ -S -0 
_vgabios-stdvga-debug_.c
+       sed -e 's/^\.text//' -e 's/^\.data//' vgabios-stdvga-debug.s > 
_vgabios-stdvga-debug_.s
+       $(AS86) _vgabios-stdvga-debug_.s -b vgabios-stdvga-debug.bin -u -w- -g 
-0 -j -O -l vgabios-stdvga-debug.txt
+       rm -f _vgabios-stdvga-debug_.s _vgabios-stdvga-debug_.c 
vgabios-stdvga-debug.s
+       cp vgabios-stdvga-debug.bin VGABIOS-lgpl-latest.stdvga.debug.bin
+       ./biossums VGABIOS-lgpl-latest.stdvga.debug.bin
+       ls -l VGABIOS-lgpl-latest.stdvga.debug.bin
+
 vgabios-cirrus.bin: biossums vgabios.c vgabios.h vgafonts.h vgatables.h clext.c
        $(GCC) -E -P vgabios.c $(VGABIOS_VERS) -DCIRRUS -DPCIBIOS 
$(VGABIOS_DATE) > _vgabios-cirrus_.c
        $(BCC) -o vgabios-cirrus.s -C-c -D__i86__ -S -0 _vgabios-cirrus_.c
diff --git a/tools/firmware/vgabios/vbe.c b/tools/firmware/vgabios/vbe.c
index c506690..d7706f5 100644
--- a/tools/firmware/vgabios/vbe.c
+++ b/tools/firmware/vgabios/vbe.c
@@ -914,6 +914,7 @@ Bit16u *AX;Bit16u CX; Bit16u ES;Bit16u DI;
         ModeInfoListItem  *cur_info;
         Boolean           using_lfb;
         ModeInfoBlockCompact   info;
+        Bit16u            lfb_addr=0;
 
 #ifdef DEBUG
         printf("VBE vbe_biosfn_return_mode_information ES%x DI%x 
CX%x\n",ES,DI,CX);
@@ -957,6 +958,14 @@ Bit16u *AX;Bit16u CX; Bit16u ES;Bit16u DI;
                 outw(VBE_DISPI_IOPORT_INDEX,VBE_DISPI_INDEX_LFB_ADDRESS_L);
                 info.PhysBasePtr |= inw(VBE_DISPI_IOPORT_DATA);
 #endif                                                         
+#ifdef PCI_VID
+                if ((Bit16u)(info.PhysBasePtr >> 16) == 0 &&
+                    (Bit16u)info.PhysBasePtr == 0)
+                  lfb_addr = pci_get_lfb_addr(PCI_VID);
+
+                if (lfb_addr > 0)
+                  info.PhysBasePtr = ((Bit32u)lfb_addr << 16);
+#endif
                 result = 0x4f;
 
                 // copy updates in mode_info_block back
diff --git a/tools/firmware/vgabios/vgabios.c b/tools/firmware/vgabios/vgabios.c
index 1c75b7d..22471c5 100644
--- a/tools/firmware/vgabios/vgabios.c
+++ b/tools/firmware/vgabios/vgabios.c
@@ -209,8 +209,13 @@ vgabios_pci_data:
 .word 0x1013
 .word 0x00b8 // CLGD5446
 #else
+#ifdef PCI_VID
+.word PCI_VID
+.word PCI_DID
+#else
 #error "Unknown PCI vendor and device id"
 #endif
+#endif
 .word 0 // reserved
 .word 0x18 // dlen
 .byte 0 // revision
@@ -3829,6 +3834,69 @@ void printf(s)
 }
 #endif
 
+ASM_START
+  ; get LFB address from PCI
+  ; in - ax: PCI device vendor
+  ; out - ax: LFB address (high 16 bit)
+  ;; NOTE - may be called in protected mode
+_pci_get_lfb_addr:
+  push bx
+  push cx
+  push dx
+  push eax
+    mov bx, ax
+    xor cx, cx
+    mov dl, #0x00
+    call pci_read_reg
+    cmp ax, #0xffff
+    jz pci_get_lfb_addr_fail
+ pci_get_lfb_addr_next_dev:
+    mov dl, #0x00
+    call pci_read_reg
+    cmp ax, bx ;; check vendor
+    jz pci_get_lfb_addr_found
+    add cx, #0x8
+    cmp cx, #0x200 ;; search bus #0 and #1
+    jb pci_get_lfb_addr_next_dev
+ pci_get_lfb_addr_fail:
+    xor dx, dx ;; no LFB
+    jmp pci_get_lfb_addr_return
+ pci_get_lfb_addr_found:
+    mov dl, #0x10 ;; I/O space #0
+    call pci_read_reg
+    test ax, #0xfff1
+    jz pci_get_lfb_addr_success
+    mov dl, #0x14 ;; I/O space #1
+    call pci_read_reg
+    test ax, #0xfff1
+    jnz pci_get_lfb_addr_fail
+ pci_get_lfb_addr_success:
+    shr eax, #16
+    mov dx, ax ;; LFB address
+ pci_get_lfb_addr_return:
+  pop eax
+  mov ax, dx
+  pop dx
+  pop cx
+  pop bx
+  ret
+
+  ; read PCI register
+  ; in - cx: device/function
+  ; in - dl: register
+  ; out - eax: value
+pci_read_reg:
+  mov eax, #0x00800000
+  mov ax, cx
+  shl eax, #8
+  mov al, dl
+  mov dx, #0xcf8
+  out dx, eax
+  add dl, #4
+  in  eax, dx
+  ret
+ASM_END
+
 #ifdef VBE
 #include "vbe.c"
 #endif
-- 
2.7.4


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