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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2 03/10] libx86: Introduce x86_cpu_policies_are_compatible()
This helper will eventually be the core "can a guest configured like this run
on the CPU?" logic. For now, it is just enough of a stub to allow us to
replace the hypercall interface while retaining the previous behaviour.
It will be expanded as various other bits of CPUID handling get cleaned up.
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
v2:
* Rebase over 'plaform' typo fix
* Proactively initialise the error pointer
* Expand the function documentation
---
tools/tests/cpu-policy/Makefile | 2 +-
tools/tests/cpu-policy/test-cpu-policy.c | 111 ++++++++++++++++++++++++++++++-
xen/include/xen/lib/x86/cpu-policy.h | 26 ++++++++
xen/lib/x86/Makefile | 1 +
xen/lib/x86/policy.c | 54 +++++++++++++++
5 files changed, 191 insertions(+), 3 deletions(-)
create mode 100644 xen/lib/x86/policy.c
diff --git a/tools/tests/cpu-policy/Makefile b/tools/tests/cpu-policy/Makefile
index fb548c9b9a..70ff154da6 100644
--- a/tools/tests/cpu-policy/Makefile
+++ b/tools/tests/cpu-policy/Makefile
@@ -39,7 +39,7 @@ CFLAGS += $(APPEND_CFLAGS)
vpath %.c ../../../xen/lib/x86
-test-cpu-policy: test-cpu-policy.o msr.o cpuid.o
+test-cpu-policy: test-cpu-policy.o msr.o cpuid.o policy.o
$(CC) $(CFLAGS) $^ -o $@
-include $(DEPS_INCLUDE)
diff --git a/tools/tests/cpu-policy/test-cpu-policy.c
b/tools/tests/cpu-policy/test-cpu-policy.c
index 201358d210..20ebed923b 100644
--- a/tools/tests/cpu-policy/test-cpu-policy.c
+++ b/tools/tests/cpu-policy/test-cpu-policy.c
@@ -9,8 +9,7 @@
#include <xen-tools/libs.h>
#include <xen/asm/x86-vendors.h>
-#include <xen/lib/x86/cpuid.h>
-#include <xen/lib/x86/msr.h>
+#include <xen/lib/x86/cpu-policy.h>
#include <xen/domctl.h>
static unsigned int nr_failures;
@@ -503,6 +502,111 @@ static void test_cpuid_out_of_range_clearing(void)
}
}
+static void test_is_compatible_success(void)
+{
+ static struct test {
+ const char *name;
+ struct cpuid_policy host_cpuid;
+ struct cpuid_policy guest_cpuid;
+ struct msr_policy host_msr;
+ struct msr_policy guest_msr;
+ } tests[] = {
+ {
+ .name = "Host CPUID faulting, Guest not",
+ .host_msr = {
+ .platform_info.cpuid_faulting = true,
+ },
+ },
+ {
+ .name = "Host CPUID faulting, Guest wanted",
+ .host_msr = {
+ .platform_info.cpuid_faulting = true,
+ },
+ .guest_msr = {
+ .platform_info.cpuid_faulting = true,
+ },
+ },
+ };
+ struct cpu_policy_errors no_errors = INIT_CPU_POLICY_ERRORS;
+
+ printf("Testing policy compatibility success:\n");
+
+ for ( size_t i = 0; i < ARRAY_SIZE(tests); ++i )
+ {
+ struct test *t = &tests[i];
+ struct cpu_policy sys = {
+ &t->host_cpuid,
+ &t->host_msr,
+ }, new = {
+ &t->guest_cpuid,
+ &t->guest_msr,
+ };
+ struct cpu_policy_errors e;
+ int res = x86_cpu_policies_are_compatible(&sys, &new, &e);
+
+ /* Check the expected error output. */
+ if ( res != 0 || memcmp(&no_errors, &e, sizeof(no_errors)) )
+ fail(" Test '%s' expected no errors\n"
+ " got res %d { leaf %08x, subleaf %08x, msr %08x }\n",
+ t->name, res, e.leaf, e.subleaf, e.msr);
+ }
+}
+
+static void test_is_compatible_failure(void)
+{
+ static struct test {
+ const char *name;
+ struct cpuid_policy host_cpuid;
+ struct cpuid_policy guest_cpuid;
+ struct msr_policy host_msr;
+ struct msr_policy guest_msr;
+ struct cpu_policy_errors e;
+ } tests[] = {
+ {
+ .name = "Host basic.max_leaf out of range",
+ .guest_cpuid.basic.max_leaf = 1,
+ .e = { 0, -1, -1 },
+ },
+ {
+ .name = "Host extd.max_leaf out of range",
+ .guest_cpuid.extd.max_leaf = 1,
+ .e = { 0x80000008, -1, -1 },
+ },
+ {
+ .name = "Host no CPUID faulting, Guest wanted",
+ .guest_msr = {
+ .platform_info.cpuid_faulting = true,
+ },
+ .e = { -1, -1, 0xce },
+ },
+ };
+
+ printf("Testing policy compatibility failure:\n");
+
+ for ( size_t i = 0; i < ARRAY_SIZE(tests); ++i )
+ {
+ struct test *t = &tests[i];
+ struct cpu_policy sys = {
+ &t->host_cpuid,
+ &t->host_msr,
+ }, new = {
+ &t->guest_cpuid,
+ &t->guest_msr,
+ };
+ struct cpu_policy_errors e;
+ int res = x86_cpu_policies_are_compatible(&sys, &new, &e);
+
+ /* Check the expected error output. */
+ if ( res == 0 || memcmp(&t->e, &e, sizeof(t->e)) )
+ fail(" Test '%s' res %d\n"
+ " expected { leaf %08x, subleaf %08x, msr %08x }\n"
+ " got { leaf %08x, subleaf %08x, msr %08x }\n",
+ t->name, res,
+ t->e.leaf, t->e.subleaf, t->e.msr,
+ e.leaf, e.subleaf, e.msr);
+ }
+}
+
int main(int argc, char **argv)
{
printf("CPU Policy unit tests\n");
@@ -516,6 +620,9 @@ int main(int argc, char **argv)
test_msr_serialise_success();
test_msr_deserialise_failure();
+ test_is_compatible_success();
+ test_is_compatible_failure();
+
if ( nr_failures )
printf("Done: %u failures\n", nr_failures);
else
diff --git a/xen/include/xen/lib/x86/cpu-policy.h
b/xen/include/xen/lib/x86/cpu-policy.h
index 6f07c4b493..b7e38732a0 100644
--- a/xen/include/xen/lib/x86/cpu-policy.h
+++ b/xen/include/xen/lib/x86/cpu-policy.h
@@ -11,6 +11,32 @@ struct cpu_policy
struct msr_policy *msr;
};
+struct cpu_policy_errors
+{
+ uint32_t leaf, subleaf;
+ uint32_t msr;
+};
+
+#define INIT_CPU_POLICY_ERRORS { ~0u, ~0u, ~0u }
+
+/*
+ * Calculate whether two policies are compatible.
+ *
+ * i.e. Can a VM configured with @guest run on a CPU supporting @host.
+ *
+ * @param host A cpu_policy describing the hardware capabilities.
+ * @param guest A cpu_policy describing the intended VM configuration.
+ * @param err Optional hint for error diagnostics.
+ * @returns -errno
+ *
+ * For typical usage, @host should be a system policy. In the case that an
+ * incompatibility is detected, the optional err pointer may identify the
+ * problematic leaf/subleaf and/or MSR.
+ */
+int x86_cpu_policies_are_compatible(const struct cpu_policy *host,
+ const struct cpu_policy *guest,
+ struct cpu_policy_errors *err);
+
#endif /* !XEN_LIB_X86_POLICIES_H */
/*
diff --git a/xen/lib/x86/Makefile b/xen/lib/x86/Makefile
index 2f9691e964..780ea05db1 100644
--- a/xen/lib/x86/Makefile
+++ b/xen/lib/x86/Makefile
@@ -1,2 +1,3 @@
obj-y += cpuid.o
obj-y += msr.o
+obj-y += policy.o
diff --git a/xen/lib/x86/policy.c b/xen/lib/x86/policy.c
new file mode 100644
index 0000000000..33a347ff9b
--- /dev/null
+++ b/xen/lib/x86/policy.c
@@ -0,0 +1,54 @@
+#include "private.h"
+
+#include <xen/lib/x86/cpu-policy.h>
+
+int x86_cpu_policies_are_compatible(const struct cpu_policy *host,
+ const struct cpu_policy *guest,
+ struct cpu_policy_errors *err)
+{
+ struct cpu_policy_errors e = INIT_CPU_POLICY_ERRORS;
+ int ret = -EINVAL;
+
+ if ( err )
+ *err = e;
+
+#define NA XEN_CPUID_NO_SUBLEAF
+#define FAIL_CPUID(l, s) \
+ do { e.leaf = (l); e.subleaf = (s); goto out; } while ( 0 )
+#define FAIL_MSR(m) \
+ do { e.msr = (m); goto out; } while ( 0 )
+
+ if ( guest->cpuid->basic.max_leaf > host->cpuid->basic.max_leaf )
+ FAIL_CPUID(0, NA);
+
+ if ( guest->cpuid->extd.max_leaf > host->cpuid->extd.max_leaf )
+ FAIL_CPUID(0x80000008, NA);
+
+ /* TODO: Audit more CPUID data. */
+
+ if ( ~host->msr->platform_info.raw & guest->msr->platform_info.raw )
+ FAIL_MSR(MSR_INTEL_PLATFORM_INFO);
+
+#undef FAIL_MSR
+#undef FAIL_CPUID
+#undef NA
+
+ /* Success. */
+ ret = 0;
+
+ out:
+ if ( ret && err )
+ *err = e;
+
+ return ret;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
--
2.11.0
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