Re: [SeaBIOS] [PATCH v3] config: allow DEBUG_IO for !QEMU
On 06/01/13 05:35, Kevin O'Connor wrote: The plan on uefi was to use the smbios tables to detect qemu. Once detection is in place, the DEBUG_IO support could be made dependent on QEMU_HARDWARE and only activated after detection succeeds. Understood. I wasn't aware this was pending on me (skimmed src/csm.c). I'll see what I can do in OvmfPkg/SmbiosPlatformDxe. Doesn't seem particularly easy, given that qemu may optionally pass smbios structures over fw_cfg (see the -smbios option, in which case OVMF should not build, just install them), plus there's a big number of mandatory smbios structures for which almost a full system configuration must be collected, seemingly. I hope edk2 will at least provide the data types. Thanks Laszlo ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] [PATCH v3] config: allow DEBUG_IO for !QEMU
On 05/31/13 03:09, Kevin O'Connor wrote: On Thu, May 30, 2013 at 09:30:33AM +0200, Gerd Hoffmann wrote: On 05/30/13 03:34, Kevin O'Connor wrote: On Wed, May 29, 2013 at 04:25:59PM +0200, Gerd Hoffmann wrote: Allow selecting DEBUG_IO for non-qemu configurations, which is useful when running coreboot+seabios on qemu. Unfortunately, if one does run seabios on real hardware and has DEBUG_IO enabled, it will write to IO port 0x402 before confirming that it is actually running on QEMU. This could cause mysterious failures on real hardware if something is listening to that port. It's why I left the option dependent on QEMU instead of QEMU_HARDWARE. Ideally the code would verify it is on QEMU before using the IO port, while still providing the very early debugging when it is known to be safe. The debgconsole port returns 0xe9 on reads, so we could use that for probing and do something like the attached patch. Which doesn't build for some reason. Is the F segment read-only in 16bit mode? Should I use something else instead? Or #ifdef the SET_GLOBAL for 32bit mode, which should work fine given that POST runs in 32bit mode? Same problem - one can't reliably do an inb(0xe9) on real hardware without risking mysterious failures. This entire problem seems to exist only if someone runs a SeaBIOS binary on real hardware that was configured like: - COREBOOT or CSM (ie. not QEMU), - and QEMU_HARDWARE. Why would someone set QEMU_HARDWARE (Support hardware found on emulators) for a binary intended to run on real hardware? In the rest of src/Kconfig, the following options depend on QEMU_HARDWARE: - VIRTIO_BLK - VIRTIO_SCSI - ESP_SCSI - LSI_SCSI The first two clearly don't make sense on bare metal. The last two might (no idea), but if that's the case, then their dependency on emulated hardware is wrong. We need a way to say in Kconfig, this is a CSM build specifically meant for emulators, and CONFIG_CSM + QEMU_HARDWARE looks like an ideal candidate. People building for bare metal shouldn't (need to) set QEMU_HARDWARE. Alternatively, we need code that can run in 16-bit mode (consequently, without writing any globals) and that can identify *any* of the supported hypervisors. PlatformRunningOn is too late. KVM and Xen could be covered by cpuid() (*), but this approach is a pain because a single patch would have to add detection for all supported hypervisors at once. (*) I checked the SDM and also there's code like this out there, eg. http://lkml.indiana.edu/hypermail/linux/kernel/0705.0/0019.html. What if we replace the inb() in the proposed patch with a cpuid call that detects only KVM, as first step? On KVM it would do the right thing, on bare metal, ditto. On other hypervisors it would err towards safety and could be extended later. What do you think? Thanks, Laszlo ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] [PATCH v3] config: allow DEBUG_IO for !QEMU
On Fri, May 31, 2013 at 03:30:48PM +0200, Laszlo Ersek wrote: On 05/31/13 03:09, Kevin O'Connor wrote: Same problem - one can't reliably do an inb(0xe9) on real hardware without risking mysterious failures. This entire problem seems to exist only if someone runs a SeaBIOS binary on real hardware that was configured like: - COREBOOT or CSM (ie. not QEMU), - and QEMU_HARDWARE. Why would someone set QEMU_HARDWARE (Support hardware found on emulators) for a binary intended to run on real hardware? It's common to build seabios with all options enabled and let seabios auto-detect what it can use. That's the intent of QEMU_HARDWARE - it allows one to compile in more drivers and seabios will use them if it detects the corresponding hardware. This does not obviate the need for proper hardware detection though. If this goes wrong on real hardware, it could require a lengthy session with a soldering iron to fix it. People don't like that. [...] What if we replace the inb() in the proposed patch with a cpuid call that detects only KVM, as first step? On KVM it would do the right thing, on bare metal, ditto. On other hypervisors it would err towards safety and could be extended later. What do you think? The plan was to detect qemu on coreboot via the mainboard vendor/part info that coreboot generates. The plan on uefi was to use the smbios tables to detect qemu. Once detection is in place, the DEBUG_IO support could be made dependent on QEMU_HARDWARE and only activated after detection succeeds. -Kevin ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] [PATCH v3] config: allow DEBUG_IO for !QEMU
On 05/30/13 03:34, Kevin O'Connor wrote:
On Wed, May 29, 2013 at 04:25:59PM +0200, Gerd Hoffmann wrote:
Allow selecting DEBUG_IO for non-qemu configurations,
which is useful when running coreboot+seabios on qemu.
Unfortunately, if one does run seabios on real hardware and has
DEBUG_IO enabled, it will write to IO port 0x402 before confirming
that it is actually running on QEMU. This could cause mysterious
failures on real hardware if something is listening to that port.
It's why I left the option dependent on QEMU instead of QEMU_HARDWARE.
Ideally the code would verify it is on QEMU before using the IO port,
while still providing the very early debugging when it is known to be
safe.
The debgconsole port returns 0xe9 on reads, so we could use that for
probing and do something like the attached patch. Which doesn't build
for some reason. Is the F segment read-only in 16bit mode? Should I
use something else instead? Or #ifdef the SET_GLOBAL for 32bit mode,
which should work fine given that POST runs in 32bit mode?
cheers,
Gerd
From ea131715b0b8f959f8f34768ef46ac029a5f84b0 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann kra...@redhat.com
Date: Thu, 30 May 2013 09:25:40 +0200
Subject: [PATCH] [broken] probe for debug port
Signed-off-by: Gerd Hoffmann kra...@redhat.com
---
src/output.c | 13 +++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/src/output.c b/src/output.c
index 79c3ada..102f177 100644
--- a/src/output.c
+++ b/src/output.c
@@ -24,6 +24,7 @@ struct putcinfo {
#define DEBUG_TIMEOUT 10
u16 DebugOutputPort VARFSEG = 0x402;
+u8 DebugOutputEnabled VARFSEG = 0xff;
void
debug_serial_preinit(void)
@@ -77,9 +78,17 @@ putc_debug(struct putcinfo *action, char c)
{
if (! CONFIG_DEBUG_LEVEL)
return;
-if (CONFIG_DEBUG_IO)
+if (CONFIG_DEBUG_IO) {
// Send character to debug port.
-outb(c, GET_GLOBAL(DebugOutputPort));
+u8 enabled = GET_GLOBAL(DebugOutputEnabled);
+if (enabled == 0xff) {
+enabled = (inb(GET_GLOBAL(DebugOutputPort)) == 0xe9);
+SET_GLOBAL(DebugOutputEnabled, enabled);
+}
+if (enabled ) {
+outb(c, GET_GLOBAL(DebugOutputPort));
+}
+}
if (c == '\n')
debug_serial('\r');
debug_serial(c);
--
1.7.9.7
___
SeaBIOS mailing list
SeaBIOS@seabios.org
http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] [PATCH v3] config: allow DEBUG_IO for !QEMU
Gerd Hoffmann wrote: Allow selecting DEBUG_IO for non-qemu configurations, which is useful when running coreboot+seabios on qemu. [ v2: QEMU_HARDWARE is even better as DEBUG_IO default value ] [ v3: make QEMU_HARDWARE usage consistent with other config options, fix spellings in commit message ] Signed-off-by: Gerd Hoffmann kra...@redhat.com Acked-by: Peter Stuge pe...@stuge.se ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] [PATCH v3] config: allow DEBUG_IO for !QEMU
On Thu, May 30, 2013 at 09:30:33AM +0200, Gerd Hoffmann wrote: On 05/30/13 03:34, Kevin O'Connor wrote: On Wed, May 29, 2013 at 04:25:59PM +0200, Gerd Hoffmann wrote: Allow selecting DEBUG_IO for non-qemu configurations, which is useful when running coreboot+seabios on qemu. Unfortunately, if one does run seabios on real hardware and has DEBUG_IO enabled, it will write to IO port 0x402 before confirming that it is actually running on QEMU. This could cause mysterious failures on real hardware if something is listening to that port. It's why I left the option dependent on QEMU instead of QEMU_HARDWARE. Ideally the code would verify it is on QEMU before using the IO port, while still providing the very early debugging when it is known to be safe. The debgconsole port returns 0xe9 on reads, so we could use that for probing and do something like the attached patch. Which doesn't build for some reason. Is the F segment read-only in 16bit mode? Should I use something else instead? Or #ifdef the SET_GLOBAL for 32bit mode, which should work fine given that POST runs in 32bit mode? Same problem - one can't reliably do an inb(0xe9) on real hardware without risking mysterious failures. -Kevin ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
[SeaBIOS] [PATCH v3] config: allow DEBUG_IO for !QEMU
Allow selecting DEBUG_IO for non-qemu configurations, which is useful when running coreboot+seabios on qemu. [ v2: QEMU_HARDWARE is even better as DEBUG_IO default value ] [ v3: make QEMU_HARDWARE usage consistent with other config options, fix spellings in commit message ] Signed-off-by: Gerd Hoffmann kra...@redhat.com --- src/Kconfig |2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/Kconfig b/src/Kconfig index 3c80132..5882d11 100644 --- a/src/Kconfig +++ b/src/Kconfig @@ -425,7 +425,7 @@ menu Debugging Base port for serial - generally 0x3f8, 0x2f8, 0x3e8, or 0x2e8. config DEBUG_IO -depends on QEMU DEBUG_LEVEL != 0 +depends on QEMU_HARDWARE DEBUG_LEVEL != 0 bool Special IO port debugging default y help -- 1.7.9.7 ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] [PATCH v3] config: allow DEBUG_IO for !QEMU
On 05/29/13 16:25, Gerd Hoffmann wrote: Allow selecting DEBUG_IO for non-qemu configurations, which is useful when running coreboot+seabios on qemu. [ v2: QEMU_HARDWARE is even better as DEBUG_IO default value ] [ v3: make QEMU_HARDWARE usage consistent with other config options, fix spellings in commit message ] Signed-off-by: Gerd Hoffmann kra...@redhat.com --- src/Kconfig |2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/Kconfig b/src/Kconfig index 3c80132..5882d11 100644 --- a/src/Kconfig +++ b/src/Kconfig @@ -425,7 +425,7 @@ menu Debugging Base port for serial - generally 0x3f8, 0x2f8, 0x3e8, or 0x2e8. config DEBUG_IO -depends on QEMU DEBUG_LEVEL != 0 +depends on QEMU_HARDWARE DEBUG_LEVEL != 0 bool Special IO port debugging default y help QEMU selects QEMU_HARDWARE, so OK in that direction. CSM and COREBOOT (!QEMU in general) make the QEMU_HARDWARE option available, which when set to y opens up DEBUG_IO. Reviewed-by: Laszlo Ersek ler...@redhat.com Thanks Laszlo ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] [PATCH v3] config: allow DEBUG_IO for !QEMU
On Wed, May 29, 2013 at 04:25:59PM +0200, Gerd Hoffmann wrote: Allow selecting DEBUG_IO for non-qemu configurations, which is useful when running coreboot+seabios on qemu. Unfortunately, if one does run seabios on real hardware and has DEBUG_IO enabled, it will write to IO port 0x402 before confirming that it is actually running on QEMU. This could cause mysterious failures on real hardware if something is listening to that port. It's why I left the option dependent on QEMU instead of QEMU_HARDWARE. Ideally the code would verify it is on QEMU before using the IO port, while still providing the very early debugging when it is known to be safe. -Kevin ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
