[PATCH] cpu: msr: GPF avoidance on BOCHs QEMU systems (LP: #925001)

[Colin King]

From: Colin Ian King <colin.king at canonical.com>

Bochs firmware based QEMU systems on some configurations get
General Protection Faults when running the MSR tests.  Since this
isn't real hardware that we care about we can just kludge around
this by not allowing the MSR tests in Bochs based systems.

Signed-off-by: Colin Ian King <colin.king at canonical.com>
---
 src/cpu/msr/msr.c |   19 +++++++++++++++++++
 1 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/src/cpu/msr/msr.c b/src/cpu/msr/msr.c
index d6aa00e..5de27a7 100644
--- a/src/cpu/msr/msr.c
+++ b/src/cpu/msr/msr.c
@@ -30,6 +30,8 @@ static fwts_cpuinfo_x86 *cpuinfo;
 
 static int msr_init(fwts_framework *fw)
 {
+	char *bios_vendor;
+
 	if ((cpuinfo = fwts_cpu_get_info(0)) == NULL) {
 		fwts_log_error(fw, "Cannot get CPU info");
 		return FWTS_ERROR;
@@ -45,6 +47,23 @@ static int msr_init(fwts_framework *fw)
 		fwts_log_error(fw, "Cannot detect the number of CPUs on this machine.");
 		return FWTS_ABORTED;
 	}
+
+	/*
+	 * Running MSR tests inside virtual machines such as QEMU with some kernel/kvm
+	 * combinations have been observed to cause GPFs.  We kludge around this by
+	 * avoiding MSR tests for a Bochs BIOS based QEMU virtual machine.
+	 */
+	if ((bios_vendor = fwts_get("/sys/class/dmi/id/bios_vendor")) != NULL) {
+		if (strstr(bios_vendor, "Bochs")) {
+			fwts_log_error(fw,
+				"MSR test being avoiding inside a virtual machine as "
+				"this is known to cause General Protection Faults on "
+				"some configurations.");
+			free(bios_vendor);
+			return FWTS_SKIP;
+		}
+		free(bios_vendor);
+	}
 	return FWTS_OK;
 }
 
-- 
1.7.8.3