Older Xen versions used to expose some CPUID bits which are no longer
exposed by default. In order to keep a compatible behavior with
guests migrated from versions of Xen that don't encode the CPUID data
on the migration stream introduce a function that sets the same bits
as older Xen versions.
This is pulled out from xc_cpuid_apply_policy which already has this
logic present.
No functional change intended.
Signed-off-by: Roger Pau Monné <roger....@citrix.com>
---
tools/include/xenctrl.h | 4 ++++
tools/libs/guest/xg_cpuid_x86.c | 39 ++++++++++++++++++++++++++++-----
2 files changed, 37 insertions(+), 6 deletions(-)
diff --git a/tools/include/xenctrl.h b/tools/include/xenctrl.h
index 5f3e5e17e9d..6f7158156fa 100644
--- a/tools/include/xenctrl.h
+++ b/tools/include/xenctrl.h
@@ -2627,6 +2627,10 @@ int xc_cpu_policy_calc_compatible(xc_interface *xch,
const xc_cpu_policy_t p2,
xc_cpu_policy_t out);
+/* Make a policy compatible with previous Xen versions. */
+int xc_cpu_policy_make_compatible(xc_interface *xch, xc_cpu_policy_t policy,
+ bool hvm);
+
int xc_get_cpu_levelling_caps(xc_interface *xch, uint32_t *caps);
int xc_get_cpu_featureset(xc_interface *xch, uint32_t index,
uint32_t *nr_features, uint32_t *featureset);
diff --git a/tools/libs/guest/xg_cpuid_x86.c b/tools/libs/guest/xg_cpuid_x86.c
index 4afca3249ba..2abaf400a2b 100644
--- a/tools/libs/guest/xg_cpuid_x86.c
+++ b/tools/libs/guest/xg_cpuid_x86.c
@@ -436,6 +436,7 @@ int xc_cpuid_apply_policy(xc_interface *xch, uint32_t
domid, bool restore,
unsigned int i, nr_leaves, nr_msrs;
xen_cpuid_leaf_t *leaves = NULL;
struct cpuid_policy *p = NULL;
+ struct cpu_policy policy = { };
uint32_t err_leaf = -1, err_subleaf = -1, err_msr = -1;
uint32_t host_featureset[FEATURESET_NR_ENTRIES] = {};
uint32_t len = ARRAY_SIZE(host_featureset);
@@ -504,12 +505,8 @@ int xc_cpuid_apply_policy(xc_interface *xch, uint32_t
domid, bool restore,
*/
if ( restore )
{
- p->basic.rdrand = test_bit(X86_FEATURE_RDRAND, host_featureset);
-
- if ( di.hvm )
- {
- p->feat.mpx = test_bit(X86_FEATURE_MPX, host_featureset);
- }
+ policy.cpuid = p;
+ xc_cpu_policy_make_compatible(xch, &policy, di.hvm);
}
if ( featureset )
@@ -1230,3 +1227,33 @@ int xc_cpu_policy_calc_compatible(xc_interface *xch,
return rc;
}
+
+int xc_cpu_policy_make_compatible(xc_interface *xch, xc_cpu_policy_t policy,
+ bool hvm)
+{
+ xc_cpu_policy_t host;
+ int rc;
+
+ host = xc_cpu_policy_init();
+ if ( !host )
+ {
+ errno = ENOMEM;
+ return -1;
+ }
+
+ rc = xc_cpu_policy_get_system(xch, XEN_SYSCTL_cpu_policy_host, host);
+ if ( rc )
+ {
+ ERROR("Failed to get host policy");
+ goto out;
+ }
+
+ policy->cpuid->basic.rdrand = host->cpuid->basic.rdrand;
+
+ if ( hvm )
+ policy->cpuid->feat.mpx = host->cpuid->feat.mpx;
+
+ out:
+ xc_cpu_policy_destroy(host);
+ return rc;
+}
--
2.30.1
