| Message ID | 20210323095849.37858-17-roger.pau@citrix.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | libs/guest: new CPUID/MSR interface | expand |
On 23.03.2021 10:58, Roger Pau Monne wrote: > --- 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); > } The comment ahead of this if() wants moving to ... > @@ -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; ... or cloning ahead of these two. Jan
On 23/03/2021 09:58, Roger Pau Monne wrote: > 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@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); I think this probably wants "pre-4.14(?)" somewhere obvious, because "compatible" on its own is very ambiguous. ~Andrew
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; +}
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@citrix.com> --- tools/include/xenctrl.h | 4 ++++ tools/libs/guest/xg_cpuid_x86.c | 39 ++++++++++++++++++++++++++++----- 2 files changed, 37 insertions(+), 6 deletions(-)