src/fw/shadow.c | 14 +++++++++++++- src/hw/pci.c | 1 - src/hw/pci.h | 2 ++ src/resume.c | 4 ++-- src/util.h | 2 +- 5 files changed, 18 insertions(+), 5 deletions(-)
On QEMU it's necessary to manually reset the BIOS memory region
between 0xc0000-0x100000 on a reboot. After this manual memory reset
is completed, it's not valid to use the generic reset mechanisms.
Rename qemu_prep_reset() to qemu_reboot() and change the function to
immediately reboot after the code memcpy.
This fixes a bug that could cause code corruption on reboots - calling
the udelay() function (as invoked by i8042_reboot and/or pci_reboot)
was not valid after the BIOS was memcpy'd.
Reported-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
---
This patch is based on Paolo's recommendation of first attempting a
PCI style reboot on QEMU. However, instead of next attempting a
keyboard reset, this patch attempts to signal an "INIT" via a triple
fault (as I think that's a bit simpler and less likely to fail).
---
src/fw/shadow.c | 14 +++++++++++++-
src/hw/pci.c | 1 -
src/hw/pci.h | 2 ++
src/resume.c | 4 ++--
src/util.h | 2 +-
5 files changed, 18 insertions(+), 5 deletions(-)
diff --git a/src/fw/shadow.c b/src/fw/shadow.c
index cd02d3a..c80b266 100644
--- a/src/fw/shadow.c
+++ b/src/fw/shadow.c
@@ -167,7 +167,7 @@ make_bios_readonly(void)
}
void
-qemu_prep_reset(void)
+qemu_reboot(void)
{
if (!CONFIG_QEMU || runningOnXen())
return;
@@ -187,4 +187,16 @@ qemu_prep_reset(void)
memcpy(hrp + 4, hrp + 4 + BIOS_SRC_OFFSET, cend - (hrp + 4));
barrier();
HaveRunPost = 0;
+ barrier();
+
+ // Request a QEMU system reset. Do the reset in this function as
+ // the BIOS code was overwritten above and not all BIOS
+ // functionality may be available.
+
+ // Attempt PCI style reset
+ outb(0x02, PORT_PCI_REBOOT);
+ outb(0x06, PORT_PCI_REBOOT);
+
+ // Next try triple faulting the CPU to force a reset
+ asm volatile("int3");
}
diff --git a/src/hw/pci.c b/src/hw/pci.c
index 506ee56..8e3d617 100644
--- a/src/hw/pci.c
+++ b/src/hw/pci.c
@@ -12,7 +12,6 @@
#include "x86.h" // outl
#define PORT_PCI_CMD 0x0cf8
-#define PORT_PCI_REBOOT 0x0cf9
#define PORT_PCI_DATA 0x0cfc
void pci_config_writel(u16 bdf, u32 addr, u32 val)
diff --git a/src/hw/pci.h b/src/hw/pci.h
index bf50430..ee6e196 100644
--- a/src/hw/pci.h
+++ b/src/hw/pci.h
@@ -3,6 +3,8 @@
#include "types.h" // u32
+#define PORT_PCI_REBOOT 0x0cf9
+
static inline u8 pci_bdf_to_bus(u16 bdf) {
return bdf >> 8;
}
diff --git a/src/resume.c b/src/resume.c
index 99fa34f..fb0b8a8 100644
--- a/src/resume.c
+++ b/src/resume.c
@@ -125,8 +125,8 @@ tryReboot(void)
{
dprintf(1, "Attempting a hard reboot\n");
- // Setup for reset on qemu.
- qemu_prep_reset();
+ // Use a QEMU specific reboot on QEMU
+ qemu_reboot();
// Reboot using ACPI RESET_REG
acpi_reboot();
diff --git a/src/util.h b/src/util.h
index 336eaaf..8269057 100644
--- a/src/util.h
+++ b/src/util.h
@@ -123,7 +123,7 @@ void pirtable_setup(void);
// fw/shadow.c
void make_bios_writable(void);
void make_bios_readonly(void);
-void qemu_prep_reset(void);
+void qemu_reboot(void);
// fw/smbios.c
void smbios_legacy_setup(void);
--
2.5.5
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* Kevin O'Connor (kevin@koconnor.net) wrote:
> On QEMU it's necessary to manually reset the BIOS memory region
> between 0xc0000-0x100000 on a reboot. After this manual memory reset
> is completed, it's not valid to use the generic reset mechanisms.
> Rename qemu_prep_reset() to qemu_reboot() and change the function to
> immediately reboot after the code memcpy.
>
> This fixes a bug that could cause code corruption on reboots - calling
> the udelay() function (as invoked by i8042_reboot and/or pci_reboot)
> was not valid after the BIOS was memcpy'd.
>
> Reported-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
> ---
>
> This patch is based on Paolo's recommendation of first attempting a
> PCI style reboot on QEMU. However, instead of next attempting a
> keyboard reset, this patch attempts to signal an "INIT" via a triple
> fault (as I think that's a bit simpler and less likely to fail).
Thanks, I've given this a few hours of testing and it seems to work
(this is testing on head rather than on our downstream).
Curiously I do occasionally get a KVM_EXIT_SHUTDOWN but I think that's
the triple fault you added rather than anything bad happening - it goes
away if I add a debug print before it; here's a kvm trace
from it:
qemu-system-x86-2998 [000] 347148.144515: kvm_exit: reason EXIT_IOIO rip 0xf524a info cf90110 f524b
qemu-system-x86-2998 [000] 347148.144517: kvm_pio: pio_write at 0xcf9 size 1 count 1 val 0x2
qemu-system-x86-2998 [000] 347148.144519: kvm_userspace_exit: reason KVM_EXIT_IO (2)
qemu-system-x86-2998 [000] 347148.144528: kvm_entry: vcpu 0
qemu-system-x86-2998 [000] 347148.144529: kvm_exit: reason EXIT_IOIO rip 0xf524d info cf90110 f524e
qemu-system-x86-2998 [000] 347148.144530: kvm_pio: pio_write at 0xcf9 size 1 count 1 val 0x6
qemu-system-x86-2998 [000] 347148.144531: kvm_userspace_exit: reason KVM_EXIT_IO (2)
qemu-system-x86-2998 [000] 347148.144715: kvm_entry: vcpu 0
qemu-system-x86-2998 [000] 347148.144718: kvm_exit: reason EXIT_SHUTDOWN rip 0xf524e info 0 0
qemu-system-x86-2998 [000] 347148.144727: kvm_userspace_exit: reason KVM_EXIT_SHUTDOWN (8)
qemu-system-x86-2993 [003] 347148.144881: kvm_set_irq: gsi 8 level 0 source 0
so it does look like it's directly after that outb.
f5243: ba f9 0c 00 00 mov $0xcf9,%edx
f5248: b0 02 mov $0x2,%al
f524a: ee out %al,(%dx)
f524b: b0 06 mov $0x6,%al
f524d: ee out %al,(%dx)
f524e: cc int3
So:
Tested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Dave
> ---
> src/fw/shadow.c | 14 +++++++++++++-
> src/hw/pci.c | 1 -
> src/hw/pci.h | 2 ++
> src/resume.c | 4 ++--
> src/util.h | 2 +-
> 5 files changed, 18 insertions(+), 5 deletions(-)
>
> diff --git a/src/fw/shadow.c b/src/fw/shadow.c
> index cd02d3a..c80b266 100644
> --- a/src/fw/shadow.c
> +++ b/src/fw/shadow.c
> @@ -167,7 +167,7 @@ make_bios_readonly(void)
> }
>
> void
> -qemu_prep_reset(void)
> +qemu_reboot(void)
> {
> if (!CONFIG_QEMU || runningOnXen())
> return;
> @@ -187,4 +187,16 @@ qemu_prep_reset(void)
> memcpy(hrp + 4, hrp + 4 + BIOS_SRC_OFFSET, cend - (hrp + 4));
> barrier();
> HaveRunPost = 0;
> + barrier();
> +
> + // Request a QEMU system reset. Do the reset in this function as
> + // the BIOS code was overwritten above and not all BIOS
> + // functionality may be available.
> +
> + // Attempt PCI style reset
> + outb(0x02, PORT_PCI_REBOOT);
> + outb(0x06, PORT_PCI_REBOOT);
> +
> + // Next try triple faulting the CPU to force a reset
> + asm volatile("int3");
> }
> diff --git a/src/hw/pci.c b/src/hw/pci.c
> index 506ee56..8e3d617 100644
> --- a/src/hw/pci.c
> +++ b/src/hw/pci.c
> @@ -12,7 +12,6 @@
> #include "x86.h" // outl
>
> #define PORT_PCI_CMD 0x0cf8
> -#define PORT_PCI_REBOOT 0x0cf9
> #define PORT_PCI_DATA 0x0cfc
>
> void pci_config_writel(u16 bdf, u32 addr, u32 val)
> diff --git a/src/hw/pci.h b/src/hw/pci.h
> index bf50430..ee6e196 100644
> --- a/src/hw/pci.h
> +++ b/src/hw/pci.h
> @@ -3,6 +3,8 @@
>
> #include "types.h" // u32
>
> +#define PORT_PCI_REBOOT 0x0cf9
> +
> static inline u8 pci_bdf_to_bus(u16 bdf) {
> return bdf >> 8;
> }
> diff --git a/src/resume.c b/src/resume.c
> index 99fa34f..fb0b8a8 100644
> --- a/src/resume.c
> +++ b/src/resume.c
> @@ -125,8 +125,8 @@ tryReboot(void)
> {
> dprintf(1, "Attempting a hard reboot\n");
>
> - // Setup for reset on qemu.
> - qemu_prep_reset();
> + // Use a QEMU specific reboot on QEMU
> + qemu_reboot();
>
> // Reboot using ACPI RESET_REG
> acpi_reboot();
> diff --git a/src/util.h b/src/util.h
> index 336eaaf..8269057 100644
> --- a/src/util.h
> +++ b/src/util.h
> @@ -123,7 +123,7 @@ void pirtable_setup(void);
> // fw/shadow.c
> void make_bios_writable(void);
> void make_bios_readonly(void);
> -void qemu_prep_reset(void);
> +void qemu_reboot(void);
>
> // fw/smbios.c
> void smbios_legacy_setup(void);
> --
> 2.5.5
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
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On Mon, Mar 06, 2017 at 01:49:26PM +0000, Dr. David Alan Gilbert wrote: > * Kevin O'Connor (kevin@koconnor.net) wrote: > > On QEMU it's necessary to manually reset the BIOS memory region > > between 0xc0000-0x100000 on a reboot. After this manual memory reset > > is completed, it's not valid to use the generic reset mechanisms. > > Rename qemu_prep_reset() to qemu_reboot() and change the function to > > immediately reboot after the code memcpy. > > > > This fixes a bug that could cause code corruption on reboots - calling > > the udelay() function (as invoked by i8042_reboot and/or pci_reboot) > > was not valid after the BIOS was memcpy'd. > > > > Reported-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > > Signed-off-by: Kevin O'Connor <kevin@koconnor.net> > > --- > > > > This patch is based on Paolo's recommendation of first attempting a > > PCI style reboot on QEMU. However, instead of next attempting a > > keyboard reset, this patch attempts to signal an "INIT" via a triple > > fault (as I think that's a bit simpler and less likely to fail). > > Thanks, I've given this a few hours of testing and it seems to work > (this is testing on head rather than on our downstream). Thanks. I committed this patch. -Kevin _______________________________________________ SeaBIOS mailing list SeaBIOS@seabios.org https://www.coreboot.org/mailman/listinfo/seabios
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