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// Support for enabling/disabling BIOS ram shadowing.
//
// Copyright (C) 2008-2010 Kevin O'Connor <kevin@koconnor.net>
// Copyright (C) 2006 Fabrice Bellard
//
// This file may be distributed under the terms of the GNU LGPLv3 license.
#include "config.h" // CONFIG_*
#include "dev-q35.h" // PCI_VENDOR_ID_INTEL
#include "dev-piix.h" // I440FX_PAM0
#include "hw/pci.h" // pci_config_writeb
#include "hw/pci_ids.h" // PCI_VENDOR_ID_INTEL
#include "hw/pci_regs.h" // PCI_VENDOR_ID
#include "malloc.h" // rom_get_last
#include "output.h" // dprintf
#include "paravirt.h" // runningOnXen
#include "string.h" // memset
#include "util.h" // make_bios_writable
#include "x86.h" // wbinvd
// On the emulators, the bios at 0xf0000 is also at 0xffff0000
#define BIOS_SRC_OFFSET 0xfff00000
// Enable shadowing and copy bios.
static void
__make_bios_writable_intel(u16 bdf, u32 pam0)
{
// Make ram from 0xc0000-0xf0000 writable
int clear = 0;
int i;
for (i=0; i<6; i++) {
u32 pam = pam0 + 1 + i;
int reg = pci_config_readb(bdf, pam);
if (CONFIG_OPTIONROMS_DEPLOYED && (reg & 0x11) != 0x11) {
// Need to copy optionroms to work around qemu implementation
void *mem = (void*)(BUILD_ROM_START + i * 32*1024);
memcpy((void*)BUILD_BIOS_TMP_ADDR, mem, 32*1024);
pci_config_writeb(bdf, pam, 0x33);
memcpy(mem, (void*)BUILD_BIOS_TMP_ADDR, 32*1024);
clear = 1;
} else {
pci_config_writeb(bdf, pam, 0x33);
}
}
if (clear)
memset((void*)BUILD_BIOS_TMP_ADDR, 0, 32*1024);
// Make ram from 0xf0000-0x100000 writable
int reg = pci_config_readb(bdf, pam0);
pci_config_writeb(bdf, pam0, 0x30);
if (reg & 0x10)
// Ram already present.
return;
// Copy bios.
extern u8 code32flat_start[], code32flat_end[];
memcpy(code32flat_start, code32flat_start + BIOS_SRC_OFFSET
, code32flat_end - code32flat_start);
}
static void
make_bios_writable_intel(u16 bdf, u32 pam0)
{
int reg = pci_config_readb(bdf, pam0);
if (!(reg & 0x10)) {
// QEMU doesn't fully implement the piix shadow capabilities -
// if ram isn't backing the bios segment when shadowing is
// disabled, the code itself wont be in memory. So, run the
// code from the high-memory flash location.
u32 pos = (u32)__make_bios_writable_intel + BIOS_SRC_OFFSET;
void (*func)(u16 bdf, u32 pam0) = (void*)pos;
func(bdf, pam0);
return;
}
// Ram already present - just enable writes
__make_bios_writable_intel(bdf, pam0);
}
static void
make_bios_readonly_intel(u16 bdf, u32 pam0)
{
// Flush any pending writes before locking memory.
wbinvd();
// Write protect roms from 0xc0000-0xf0000
u32 romlast = BUILD_BIOS_ADDR, rommax = BUILD_BIOS_ADDR;
if (CONFIG_WRITABLE_UPPERMEMORY)
romlast = rom_get_last();
if (CONFIG_MALLOC_UPPERMEMORY)
rommax = rom_get_max();
int i;
for (i=0; i<6; i++) {
u32 mem = BUILD_ROM_START + i * 32*1024;
u32 pam = pam0 + 1 + i;
if (romlast < mem + 16*1024 || rommax < mem + 32*1024) {
if (romlast >= mem && rommax >= mem + 16*1024)
pci_config_writeb(bdf, pam, 0x31);
break;
}
pci_config_writeb(bdf, pam, 0x11);
}
// Write protect 0xf0000-0x100000
pci_config_writeb(bdf, pam0, 0x10);
}
static int ShadowBDF = -1;
// Make the 0xc0000-0x100000 area read/writable.
void
make_bios_writable(void)
{
if (!CONFIG_QEMU || runningOnXen())
return;
dprintf(3, "enabling shadow ram\n");
// At this point, statically allocated variables can't be written,
// so do this search manually.
int bdf;
foreachbdf(bdf, 0) {
u32 vendev = pci_config_readl(bdf, PCI_VENDOR_ID);
u16 vendor = vendev & 0xffff, device = vendev >> 16;
if (vendor == PCI_VENDOR_ID_INTEL
&& device == PCI_DEVICE_ID_INTEL_82441) {
make_bios_writable_intel(bdf, I440FX_PAM0);
ShadowBDF = bdf;
return;
}
if (vendor == PCI_VENDOR_ID_INTEL
&& device == PCI_DEVICE_ID_INTEL_Q35_MCH) {
make_bios_writable_intel(bdf, Q35_HOST_BRIDGE_PAM0);
ShadowBDF = bdf;
return;
}
}
dprintf(1, "Unable to unlock ram - bridge not found\n");
}
// Make the BIOS code segment area (0xf0000) read-only.
void
make_bios_readonly(void)
{
if (!CONFIG_QEMU || runningOnXen())
return;
dprintf(3, "locking shadow ram\n");
if (ShadowBDF < 0) {
dprintf(1, "Unable to lock ram - bridge not found\n");
return;
}
u16 device = pci_config_readw(ShadowBDF, PCI_DEVICE_ID);
if (device == PCI_DEVICE_ID_INTEL_82441)
make_bios_readonly_intel(ShadowBDF, I440FX_PAM0);
else
make_bios_readonly_intel(ShadowBDF, Q35_HOST_BRIDGE_PAM0);
}
void
qemu_prep_reset(void)
{
if (!CONFIG_QEMU || runningOnXen())
return;
// QEMU doesn't map 0xc0000-0xfffff back to the original rom on a
// reset, so do that manually before invoking a hard reset.
make_bios_writable();
extern u8 code32flat_start[], code32flat_end[];
memcpy(code32flat_start, code32flat_start + BIOS_SRC_OFFSET
, code32flat_end - code32flat_start);
}
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