[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v6 06/12] libs/guest: make a cpu policy compatible with older Xen versions
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.pau@xxxxxxxxxx> --- Changes since v3: - Rename function to xc_cpu_policy_make_compat_4_12. Changes since v1: - Move comments and explicitly mention pre-4.13 Xen. --- tools/include/xenguest.h | 4 +++ tools/libs/guest/xg_cpuid_x86.c | 62 ++++++++++++++++++++++++--------- 2 files changed, 49 insertions(+), 17 deletions(-) diff --git a/tools/include/xenguest.h b/tools/include/xenguest.h index 2672fd043c..281454dc60 100644 --- a/tools/include/xenguest.h +++ b/tools/include/xenguest.h @@ -817,6 +817,10 @@ int xc_cpu_policy_get_msr(xc_interface *xch, const xc_cpu_policy_t *policy, bool xc_cpu_policy_is_compatible(xc_interface *xch, xc_cpu_policy_t *host, xc_cpu_policy_t *guest); +/* Make a policy compatible with pre-4.13 Xen versions. */ +int xc_cpu_policy_make_compat_4_12(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 67981b1711..f1115ad480 100644 --- a/tools/libs/guest/xg_cpuid_x86.c +++ b/tools/libs/guest/xg_cpuid_x86.c @@ -432,6 +432,7 @@ 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 xc_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); @@ -496,23 +497,9 @@ int xc_cpuid_apply_policy(xc_interface *xch, uint32_t domid, bool restore, if ( restore ) { - /* - * Account for feature which have been disabled by default since Xen 4.13, - * so migrated-in VM's don't risk seeing features disappearing. - */ - p->basic.rdrand = test_bit(X86_FEATURE_RDRAND, host_featureset); - p->feat.hle = test_bit(X86_FEATURE_HLE, host_featureset); - p->feat.rtm = test_bit(X86_FEATURE_RTM, host_featureset); - - if ( di.hvm ) - { - p->feat.mpx = test_bit(X86_FEATURE_MPX, host_featureset); - } - - /* Clamp maximum leaves to the ones supported on 4.12. */ - p->basic.max_leaf = min(p->basic.max_leaf, 0xdu); - p->feat.max_subleaf = 0; - p->extd.max_leaf = min(p->extd.max_leaf, 0x8000001c); + policy.cpuid = *p; + xc_cpu_policy_make_compat_4_12(xch, &policy, di.hvm); + *p = policy.cpuid; } if ( featureset ) @@ -918,3 +905,44 @@ bool xc_cpu_policy_is_compatible(xc_interface *xch, xc_cpu_policy_t *host, return false; } + +int xc_cpu_policy_make_compat_4_12(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; + } + + /* + * Account for features which have been disabled by default since Xen 4.13, + * so migrated-in VM's don't risk seeing features disappearing. + */ + policy->cpuid.basic.rdrand = host->cpuid.basic.rdrand; + policy->cpuid.feat.hle = host->cpuid.feat.hle; + policy->cpuid.feat.rtm = host->cpuid.feat.rtm; + + if ( hvm ) + policy->cpuid.feat.mpx = host->cpuid.feat.mpx; + + /* Clamp maximum leaves to the ones supported on pre-4.13. */ + policy->cpuid.basic.max_leaf = min(policy->cpuid.basic.max_leaf, 0xdu); + policy->cpuid.feat.max_subleaf = 0; + policy->cpuid.extd.max_leaf = min(policy->cpuid.extd.max_leaf, 0x8000001c); + + out: + xc_cpu_policy_destroy(host); + return rc; +} -- 2.34.1
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |