xen/sched: Remove d->is_pinned

The is_pinned field is rather odd.  It can only be activated with the
"dom0_vcpus_pin" command line option, and causes dom0 (or the late hwdom) to
have its vcpus identity pinned to pcpus.

Having dom0_vcpus_pin active disallows the use of vcpu_set_hard_affinity().
However, when a pcpu is offlined, or moved between cpupools, the affinity is
broken and reverts to cpumask_all.  This results in vcpus which are no longer
pinned, and cannot be adjusted.

A related bit of functionality is the is_pinned_vcpu() predicate.  This is
only used by x86 code, and permits the use of VCPUOP_get_physid and writeable
access to some extra MSRs.

The implementation however returns true for is_pinned (which will include
unpinned vcpus from the above scenario), *or* if the hard affinity mask only
has a single bit set (which is redundant with the intended effect of
is_pinned, but also includes other domains).

Rework the behaviour of "dom0_vcpus_pin" to only being an initial pinning
configuration, and permit full adjustment.  This allows the user to
reconfigure dom0 after the fact or fix up from the fallout of cpu hot unplug
and cpupool manipulation.

An unprivileged domain has no business using VCPUOP_get_physid, and shouldn't
be able to just because it happens to be pinned by admin choice.  All uses of
is_pinned_vcpu() should be restricted to the hardware domain, so rename it to
is_hwdom_pinned_vcpu() to avoid future misuse.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Dario Faggioli <dfaggioli@suse.com>

diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
index 6ebe36766bb5ac83de7fc22ef149ce4074564ff7..73f5407b0d361756220c0d7a19ebac3ab477c638 100644 (file)
--- a/xen/arch/x86/dom0_build.c
+++ b/xen/arch/x86/dom0_build.c
@@ -213,7 +213,7 @@ struct vcpu *__init dom0_setup_vcpu(struct domain *d,
         }
         else
         {
-            if ( !d->is_pinned && !dom0_affinity_relaxed )
+            if ( !opt_dom0_vcpus_pin && !dom0_affinity_relaxed )
                 sched_set_affinity(v, &dom0_cpus, NULL);
             sched_set_affinity(v, NULL, &dom0_cpus);
         }

diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 8d579e2cf9721b14774e4c953a9ce5341a231846..20b86fd56846a3a38cdf3f0dcaa21a40fc98fb8d 100644 (file)
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -1229,7 +1229,7 @@ arch_do_vcpu_op(
         struct vcpu_get_physid cpu_id;
 
         rc = -EINVAL;
-        if ( !is_pinned_vcpu(v) )
+        if ( !is_hwdom_pinned_vcpu(v) )
             break;
 
         cpu_id.phys_id =

diff --git a/xen/arch/x86/pv/emul-priv-op.c b/xen/arch/x86/pv/emul-priv-op.c
index 3746e2ad54ac13ee1234721f86dba1836567a7d7..84ce67c641f4755cdbba6ccb9a91371a0a7cf229 100644 (file)
--- a/xen/arch/x86/pv/emul-priv-op.c
+++ b/xen/arch/x86/pv/emul-priv-op.c
@@ -1017,7 +1017,7 @@ static int write_msr(unsigned int reg, uint64_t val,
         if ( boot_cpu_data.x86_vendor != X86_VENDOR_AMD ||
              boot_cpu_data.x86 < 0x10 || boot_cpu_data.x86 > 0x17 )
             break;
-        if ( !is_hardware_domain(currd) || !is_pinned_vcpu(curr) )
+        if ( !is_hwdom_pinned_vcpu(curr) )
             return X86EMUL_OKAY;
         if ( (rdmsr_safe(MSR_AMD64_NB_CFG, temp) != 0) ||
              ((val ^ temp) & ~(1ULL << AMD64_NB_CFG_CF8_EXT_ENABLE_BIT)) )
@@ -1030,7 +1030,7 @@ static int write_msr(unsigned int reg, uint64_t val,
         if ( boot_cpu_data.x86_vendor != X86_VENDOR_AMD ||
              boot_cpu_data.x86 < 0x10 || boot_cpu_data.x86 > 0x17 )
             break;
-        if ( !is_hardware_domain(currd) || !is_pinned_vcpu(curr) )
+        if ( !is_hwdom_pinned_vcpu(curr) )
             return X86EMUL_OKAY;
         if ( rdmsr_safe(MSR_FAM10H_MMIO_CONF_BASE, temp) != 0 )
             break;
@@ -1050,7 +1050,7 @@ static int write_msr(unsigned int reg, uint64_t val,
     case MSR_IA32_UCODE_REV:
         if ( boot_cpu_data.x86_vendor != X86_VENDOR_INTEL )
             break;
-        if ( !is_hardware_domain(currd) || !is_pinned_vcpu(curr) )
+        if ( !is_hwdom_pinned_vcpu(curr) )
             return X86EMUL_OKAY;
         if ( rdmsr_safe(reg, temp) )
             break;
@@ -1086,8 +1086,7 @@ static int write_msr(unsigned int reg, uint64_t val,
     case MSR_IA32_ENERGY_PERF_BIAS:
         if ( boot_cpu_data.x86_vendor != X86_VENDOR_INTEL )
             break;
-        if ( !is_hardware_domain(currd) || !is_pinned_vcpu(curr) ||
-             wrmsr_safe(reg, val) == 0 )
+        if ( !is_hwdom_pinned_vcpu(curr) || wrmsr_safe(reg, val) == 0 )
             return X86EMUL_OKAY;
         break;
 

diff --git a/xen/common/domain.c b/xen/common/domain.c
index 3b18f11f12dd8eb00ba662fb6527c42962c6836b..a1f8bb4f2f4f608647adcdf7daaca28d8b391585 100644 (file)
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -342,7 +342,6 @@ struct domain *domain_create(domid_t domid,
         if ( hardware_domid < 0 || hardware_domid >= DOMID_FIRST_RESERVED )
             panic("The value of hardware_dom must be a valid domain ID\n");
 
-        d->is_pinned = opt_dom0_vcpus_pin;
         d->disable_migrate = 1;
         old_hwdom = hardware_domain;
         hardware_domain = d;

diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index 60755a631ed6199bf9b9dee0464cc422d64b5ed0..76d60785e217367f15d34cabab36bcc504c9613f 100644 (file)
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -276,7 +276,7 @@ int sched_init_vcpu(struct vcpu *v, unsigned int processor)
      * Initialize affinity settings. The idler, and potentially
      * domain-0 VCPUs, are pinned onto their respective physical CPUs.
      */
-    if ( is_idle_domain(d) || d->is_pinned )
+    if ( is_idle_domain(d) || (is_hardware_domain(d) && opt_dom0_vcpus_pin) )
         sched_set_affinity(v, cpumask_of(processor), &cpumask_all);
     else
         sched_set_affinity(v, &cpumask_all, &cpumask_all);
@@ -958,9 +958,6 @@ int vcpu_set_hard_affinity(struct vcpu *v, const cpumask_t *affinity)
     cpumask_t online_affinity;
     cpumask_t *online;
 
-    if ( v->domain->is_pinned )
-        return -EINVAL;
-
     online = VCPU2ONLINE(v);
     cpumask_and(&online_affinity, affinity, online);
     if ( cpumask_empty(&online_affinity) )

diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index edee52dfe41e8b23a35aa992ca021706fdabb6fc..6d23b6d8730a7cf360199717902bf6dfb8e1b1a7 100644 (file)
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -381,8 +381,6 @@ struct domain
     bool             is_console;
     /* Is this a xenstore domain (not dom0)? */
     bool             is_xenstore;
-    /* Domain's VCPUs are pinned 1:1 to physical CPUs? */
-    bool             is_pinned;
     /* Non-migratable and non-restoreable? */
     bool             disable_migrate;
     /* Is this guest being debugged by dom0? */
@@ -961,8 +959,12 @@ static inline bool is_hvm_vcpu(const struct vcpu *v)
     return is_hvm_domain(v->domain);
 }
 
-#define is_pinned_vcpu(v) ((v)->domain->is_pinned || \
-                           cpumask_weight((v)->cpu_hard_affinity) == 1)
+static inline bool is_hwdom_pinned_vcpu(const struct vcpu *v)
+{
+    return (is_hardware_domain(v->domain) &&
+            cpumask_weight(v->cpu_hard_affinity) == 1);
+}
+
 #ifdef CONFIG_HAS_PASSTHROUGH
 #define has_iommu_pt(d) (dom_iommu(d)->status != IOMMU_STATUS_disabled)
 #define need_iommu_pt_sync(d) (dom_iommu(d)->need_sync)