On Wed, Oct 10, 2012 at 05:21:45PM -0700, Jonathan McDowell wrote:
> On Thu, Sep 27, 2012 at 02:42:11PM -0700, Jonathan McDowell wrote:
> > I have a machine with both Linux and Windows installed on the hard
> > drive. Linux runs on the bare metal and I occasionally run the Windows
> > install in a VM using KVM pointed at /dev/sda. However if I'm not quick
> > enough, or Windows decides to reboot when I'm not around to notice, the
> > grub running under KVM will decide to boot Linux and much confusion
> > ensues.
> >
> > I couldn't find an easy way to test what the running environment was, so
> > I knocked up a simple testpci command that allows me to test for the
> > existence of a PCI device and change the default boot option based on
> > that. I have:
> >
> > | if testpci 8086:1237; then
> > | set default="2"
> > | fi
> >
> > in my grub.cfg to correctly select the Windows partition if the qemu
> > provided host bridge is present.
>
> So, a v2, changing to use --vendor/--product and also adding
> --subvendor/--subproduct as it was pointed out to me that the subsystem
> information can be used to confirm the hypervisor presence. I now have:
>
> | if testpci --vendor=0x8086 --subvendor=0x1af4 --subproduct=0x1100; then
> | set default="2"
> | fi
>
> which looks for an Intel device that has a Red Hat / KVM subsystem ID.
And here's v3, which adds some minimal documentation about the new
command.
Signed-off-by: Jonathan McDowell <nood...@earth.li>
-----
=== modified file 'docs/grub.texi'
--- docs/grub.texi 2012-07-31 22:18:57 +0000
+++ docs/grub.texi 2012-10-12 22:13:23 +0000
@@ -3302,6 +3302,7 @@
* search:: Search devices by file, label, or UUID
* sendkey:: Emulate keystrokes
* set:: Set an environment variable
+* testpci:: Test for the existence of a PCI device
* true:: Do nothing, successfully
* unset:: Unset an environment variable
* uppermem:: Set the upper memory size
@@ -4068,6 +4069,18 @@
@end deffn
+@node testpci
+@subsection testpci
+
+@deffn Command testpci [@option{--vendor=VENDORID}] @
+ [@option{--product=PRODUCTID}] [@option{--subvendor VENDORID}] @
+ [@option{--subproduct PRODUCTID}]
+Test for the existence of a given PCI device. Returns true if a device
+matching the specified vendor/product and/or subvendor/subproduct information
+is found.
+@end deffn
+
+
@node true
@subsection true
=== modified file 'grub-core/Makefile.core.def'
--- grub-core/Makefile.core.def 2012-09-08 07:40:24 +0000
+++ grub-core/Makefile.core.def 2012-09-27 21:00:31 +0000
@@ -837,6 +837,12 @@
};
module = {
+ name = testpci;
+ common = commands/testpci.c;
+ enable = pci;
+};
+
+module = {
name = true;
common = commands/true.c;
};
=== added file 'grub-core/commands/testpci.c'
--- grub-core/commands/testpci.c 1970-01-01 00:00:00 +0000
+++ grub-core/commands/testpci.c 2012-10-12 22:08:21 +0000
@@ -0,0 +1,114 @@
+/* testpci.c - Test for PCI device existence. */
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2012 Free Software Foundation, Inc.
+ *
+ * GRUB is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GRUB is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GRUB. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/pci.h>
+#include <grub/dl.h>
+#include <grub/extcmd.h>
+#include <grub/misc.h>
+#include <grub/i18n.h>
+
+GRUB_MOD_LICENSE ("GPLv3+");
+
+static const struct grub_arg_option options[] =
+ {
+ {"vendor", 'v' , 0, N_("PCI vendor ID to look for"), 0, ARG_TYPE_INT},
+ {"product", 'p' , 0, N_("PCI product ID to look for"), 0, ARG_TYPE_INT},
+ {"subvendor", 's' , 0, N_("PCI subsystem vendor ID to look for"), 0,
ARG_TYPE_INT},
+ {"subproduct", 't' , 0, N_("PCI subsystem product ID to look for"), 0,
ARG_TYPE_INT},
+ {0, 0, 0, 0, 0, 0}
+ };
+
+static int pcifound;
+static grub_uint32_t pcimask, pcisubmask;
+static grub_pci_id_t pcisearch;
+static grub_pci_id_t pcisubsearch;
+
+static int NESTED_FUNC_ATTR
+grub_testpci_iter (grub_pci_device_t dev __attribute__ ((unused)),
+ grub_pci_id_t pciid)
+{
+ grub_pci_address_t addr;
+ grub_uint32_t subsystem;
+
+ if ((pciid & pcimask) != pcisearch) {
+ return 0;
+ }
+
+ if (pcisubmask != 0) {
+ addr = grub_pci_make_address (dev, GRUB_PCI_REG_SUBVENDOR);
+ subsystem = grub_pci_read (addr);
+ if ((subsystem & pcisubmask) != pcisubsearch) {
+ return 0;
+ }
+ }
+
+ pcifound = 1;
+ return 1;
+}
+
+static grub_err_t
+grub_cmd_testpci (grub_extcmd_context_t ctxt,
+ int argc __attribute__ ((unused)),
+ char **args __attribute__ ((unused)))
+{
+ struct grub_arg_list *state = ctxt->state;
+
+ pcifound = pcimask = pcisubmask = pcisearch = pcisubsearch = 0;
+
+ if (state[0].set) {
+ pcisearch |= grub_strtoull (state[0].arg, 0, 16);
+ pcimask |= 0xFFFF;
+ }
+
+ if (state[1].set) {
+ pcisearch |= (grub_strtoull (state[1].arg, 0, 16) << 16);
+ pcimask |= 0xFFFF0000;
+ }
+
+ if (state[2].set) {
+ pcisubsearch |= grub_strtoull (state[2].arg, 0, 16);
+ pcisubmask |= 0xFFFF;
+ }
+
+ if (state[3].set) {
+ pcisubsearch |= (grub_strtoull (state[3].arg, 0, 16) << 16);
+ pcisubmask |= 0xFFFF0000;
+ }
+
+ grub_pci_iterate (grub_testpci_iter);
+
+ return pcifound ? GRUB_ERR_NONE : grub_error (GRUB_ERR_TEST_FAILURE,
"false");
+}
+
+static grub_extcmd_t cmd;
+
+GRUB_MOD_INIT(testpci)
+{
+ cmd = grub_register_extcmd ("testpci", grub_cmd_testpci, 0,
+ N_("[--vendor=VENDORID] [--product=PRODUCTID] "
+ "[--subvendor=VENDORID] "
+ "[--subproduct=PRODUCTID]"),
+ N_("Test for PCI device existence."),
+ options);
+}
+
+GRUB_MOD_FINI(testpci)
+{
+ grub_unregister_extcmd (cmd);
+}
-----
J.
--
You drive a hard bargain for a seagull.
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