[PATCH v6 10/12] libs/{light,guest}: implement xc_cpuid_apply_policy in libxl

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

With the addition of the xc_cpu_policy_* now libxl can have better
control over the cpu policy, this allows removing the
xc_cpuid_apply_policy function and instead coding the required bits by
libxl in libxl__cpuid_legacy directly.

Remove xc_cpuid_apply_policy.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Reviewed-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
Changes since v4:
 - Correctly account for PVH guests being HVM in libxl__cpuid_legacy.
 - PAE option is only available to HVM guests (_not_ including PVH).

Changes since v2:
 - Use 'r' for libxc return values.
 - Fix comment about making a cpu policy compatible.
 - Use LOG*D macros.
---
 tools/include/xenctrl.h         |  18 -----
 tools/libs/guest/xg_cpuid_x86.c | 122 --------------------------------
 tools/libs/light/libxl_cpuid.c  |  92 ++++++++++++++++++++++--
 3 files changed, 86 insertions(+), 146 deletions(-)

diff --git a/tools/include/xenctrl.h b/tools/include/xenctrl.h
index 95bd5eca67..745d67c970 100644
--- a/tools/include/xenctrl.h
+++ b/tools/include/xenctrl.h
@@ -1829,24 +1829,6 @@ struct xc_xend_cpuid {
     char *policy[4];
 };
 
-/*
- * Make adjustments to the CPUID settings for a domain.
- *
- * This path is used in two cases.  First, for fresh boots of the domain, and
- * secondly for migrate-in/restore of pre-4.14 guests (where CPUID data was
- * missing from the stream).  The @restore parameter distinguishes these
- * cases, and the generated policy must be compatible with a 4.13.
- *
- * Either pass a full new @featureset (and @nr_features), or adjust individual
- * features (@pae, @itsc, @nested_virt).
- *
- * Then (optionally) apply legacy XEND overrides (@xend) to the result.
- */
-int xc_cpuid_apply_policy(xc_interface *xch,
-                          uint32_t domid, bool restore,
-                          const uint32_t *featureset,
-                          unsigned int nr_features, bool pae, bool itsc,
-                          bool nested_virt, const struct xc_xend_cpuid *xend);
 int xc_mca_op(xc_interface *xch, struct xen_mc *mc);
 int xc_mca_op_inject_v2(xc_interface *xch, unsigned int flags,
                         xc_cpumap_t cpumap, unsigned int nr_cpus);
diff --git a/tools/libs/guest/xg_cpuid_x86.c b/tools/libs/guest/xg_cpuid_x86.c
index cf202671ed..974549c0db 100644
--- a/tools/libs/guest/xg_cpuid_x86.c
+++ b/tools/libs/guest/xg_cpuid_x86.c
@@ -379,128 +379,6 @@ int xc_cpu_policy_apply_cpuid(xc_interface *xch, 
xc_cpu_policy_t *policy,
     return rc;
 }
 
-int xc_cpuid_apply_policy(xc_interface *xch, uint32_t domid, bool restore,
-                          const uint32_t *featureset, unsigned int nr_features,
-                          bool pae, bool itsc, bool nested_virt,
-                          const struct xc_xend_cpuid *cpuid)
-{
-    int rc;
-    xc_dominfo_t di;
-    unsigned int 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;
-
-    if ( xc_domain_getinfo(xch, domid, 1, &di) != 1 ||
-         di.domid != domid )
-    {
-        ERROR("Failed to obtain d%d info", domid);
-        rc = -ESRCH;
-        goto out;
-    }
-
-    rc = xc_cpu_policy_get_size(xch, &nr_leaves, &nr_msrs);
-    if ( rc )
-    {
-        PERROR("Failed to obtain policy info size");
-        rc = -errno;
-        goto out;
-    }
-
-    rc = -ENOMEM;
-    if ( (leaves = calloc(nr_leaves, sizeof(*leaves))) == NULL ||
-         (p = calloc(1, sizeof(*p))) == NULL )
-        goto out;
-
-    /* Get the domain's default policy. */
-    nr_msrs = 0;
-    rc = get_system_cpu_policy(xch, di.hvm ? XEN_SYSCTL_cpu_policy_hvm_default
-                                           : XEN_SYSCTL_cpu_policy_pv_default,
-                               &nr_leaves, leaves, &nr_msrs, NULL);
-    if ( rc )
-    {
-        PERROR("Failed to obtain %s default policy", di.hvm ? "hvm" : "pv");
-        rc = -errno;
-        goto out;
-    }
-
-    rc = x86_cpuid_copy_from_buffer(p, leaves, nr_leaves,
-                                    &err_leaf, &err_subleaf);
-    if ( rc )
-    {
-        ERROR("Failed to deserialise CPUID (err leaf %#x, subleaf %#x) (%d = 
%s)",
-              err_leaf, err_subleaf, -rc, strerror(-rc));
-        goto out;
-    }
-
-    if ( restore )
-    {
-        policy.cpuid = *p;
-        xc_cpu_policy_make_compat_4_12(xch, &policy, di.hvm);
-        *p = policy.cpuid;
-    }
-
-    if ( featureset )
-    {
-        policy.cpuid = *p;
-        rc = xc_cpu_policy_apply_featureset(xch, &policy, featureset,
-                                            nr_features);
-        if ( rc )
-        {
-            ERROR("Failed to apply featureset to policy");
-            goto out;
-        }
-        *p = policy.cpuid;
-    }
-    else
-    {
-        p->extd.itsc = itsc;
-
-        if ( di.hvm )
-        {
-            p->basic.pae = pae;
-            p->basic.vmx = nested_virt;
-            p->extd.svm = nested_virt;
-        }
-    }
-
-    policy.cpuid = *p;
-    rc = xc_cpu_policy_legacy_topology(xch, &policy, di.hvm);
-    if ( rc )
-        goto out;
-    *p = policy.cpuid;
-
-    rc = xc_cpu_policy_apply_cpuid(xch, &policy, cpuid, di.hvm);
-    if ( rc )
-        goto out;
-
-    rc = x86_cpuid_copy_to_buffer(p, leaves, &nr_leaves);
-    if ( rc )
-    {
-        ERROR("Failed to serialise CPUID (%d = %s)", -rc, strerror(-rc));
-        goto out;
-    }
-
-    rc = xc_set_domain_cpu_policy(xch, domid, nr_leaves, leaves, 0, NULL,
-                                  &err_leaf, &err_subleaf, &err_msr);
-    if ( rc )
-    {
-        PERROR("Failed to set d%d's policy (err leaf %#x, subleaf %#x, msr 
%#x)",
-               domid, err_leaf, err_subleaf, err_msr);
-        rc = -errno;
-        goto out;
-    }
-
-    rc = 0;
-
-out:
-    free(p);
-    free(leaves);
-
-    return rc;
-}
-
 xc_cpu_policy_t *xc_cpu_policy_init(void)
 {
     return calloc(1, sizeof(struct xc_cpu_policy));
diff --git a/tools/libs/light/libxl_cpuid.c b/tools/libs/light/libxl_cpuid.c
index e1acf6648d..7dcdb35a4c 100644
--- a/tools/libs/light/libxl_cpuid.c
+++ b/tools/libs/light/libxl_cpuid.c
@@ -441,9 +441,11 @@ int libxl__cpuid_legacy(libxl_ctx *ctx, uint32_t domid, 
bool restore,
                         libxl_domain_build_info *info)
 {
     GC_INIT(ctx);
+    xc_cpu_policy_t *policy = NULL;
+    bool hvm = info->type != LIBXL_DOMAIN_TYPE_PV;
     bool pae = true;
     bool itsc;
-    int r;
+    int r, rc = 0;
 
     /*
      * Gross hack.  Using libxl_defbool_val() here causes libvirt to crash in
@@ -454,6 +456,41 @@ int libxl__cpuid_legacy(libxl_ctx *ctx, uint32_t domid, 
bool restore,
      */
     bool nested_virt = info->nested_hvm.val > 0;
 
+    policy = xc_cpu_policy_init();
+    if (!policy) {
+        LOGED(ERROR, domid, "Failed to init CPU policy");
+        rc = ERROR_FAIL;
+        goto out;
+    }
+
+    r = xc_cpu_policy_get_domain(ctx->xch, domid, policy);
+    if (r) {
+        LOGED(ERROR, domid, "Failed to fetch domain CPU policy");
+        rc = ERROR_FAIL;
+        goto out;
+    }
+
+    if (restore) {
+        /*
+         * Make sure the policy is compatible with pre Xen 4.13. Note that
+         * newer Xen versions will pass policy data on the restore stream, so
+         * any adjustments done here will be superseded.
+         */
+        r = xc_cpu_policy_make_compat_4_12(ctx->xch, policy, hvm);
+        if (r) {
+            LOGED(ERROR, domid, "Failed to setup compatible CPU policy");
+            rc = ERROR_FAIL;
+            goto out;
+        }
+    }
+
+    r = xc_cpu_policy_legacy_topology(ctx->xch, policy, hvm);
+    if (r) {
+        LOGED(ERROR, domid, "Failed to setup CPU policy topology");
+        rc = ERROR_FAIL;
+        goto out;
+    }
+
     /*
      * For PV guests, PAE is Xen-controlled (it is the 'p' that differentiates
      * the xen-3.0-x86_32 and xen-3.0-x86_32p ABIs).  It is mandatory as Xen
@@ -466,6 +503,13 @@ int libxl__cpuid_legacy(libxl_ctx *ctx, uint32_t domid, 
bool restore,
      */
     if (info->type == LIBXL_DOMAIN_TYPE_HVM)
         pae = libxl_defbool_val(info->u.hvm.pae);
+    rc = libxl_cpuid_parse_config(&info->cpuid, GCSPRINTF("pae=%d", pae));
+    if (rc) {
+        LOGD(ERROR, domid, "Failed to set PAE CPUID flag");
+        rc = ERROR_FAIL;
+        goto out;
+    }
+
 
     /*
      * Advertising Invariant TSC to a guest means that the TSC frequency won't
@@ -481,14 +525,50 @@ int libxl__cpuid_legacy(libxl_ctx *ctx, uint32_t domid, 
bool restore,
      */
     itsc = (libxl_defbool_val(info->disable_migrate) ||
             info->tsc_mode == LIBXL_TSC_MODE_ALWAYS_EMULATE);
+    rc = libxl_cpuid_parse_config(&info->cpuid, GCSPRINTF("invtsc=%d", itsc));
+    if (rc) {
+        LOGD(ERROR, domid, "Failed to set Invariant TSC CPUID flag");
+        rc = ERROR_FAIL;
+        goto out;
+    }
 
-    r = xc_cpuid_apply_policy(ctx->xch, domid, restore, NULL, 0,
-                              pae, itsc, nested_virt, info->cpuid);
-    if (r)
-        LOGEVD(ERROR, -r, domid, "Failed to apply CPUID policy");
+    /* Set Nested virt CPUID bits for HVM. */
+    if (hvm) {
+        rc = libxl_cpuid_parse_config(&info->cpuid, GCSPRINTF("vmx=%d",
+                                                              nested_virt));
+        if (rc) {
+            LOGD(ERROR, domid, "Failed to set VMX CPUID flag");
+            rc = ERROR_FAIL;
+            goto out;
+        }
+
+        rc = libxl_cpuid_parse_config(&info->cpuid, GCSPRINTF("svm=%d",
+                                                              nested_virt));
+        if (rc) {
+            LOGD(ERROR, domid, "Failed to set SVM CPUID flag");
+            rc = ERROR_FAIL;
+            goto out;
+        }
+    }
+
+    /* Apply the bits from info->cpuid if any. */
+    r = xc_cpu_policy_apply_cpuid(ctx->xch, policy, info->cpuid, hvm);
+    if (r) {
+        LOGEVD(ERROR, domid, -r, "Failed to apply CPUID changes");
+        rc = ERROR_FAIL;
+        goto out;
+    }
+
+    r = xc_cpu_policy_set_domain(ctx->xch, domid, policy);
+    if (r) {
+        LOGED(ERROR, domid, "Failed to set domain CPUID policy");
+        rc = ERROR_FAIL;
+    }
 
+ out:
+    xc_cpu_policy_destroy(policy);
     GC_FREE;
-    return r ? ERROR_FAIL : 0;
+    return rc;
 }
 
 static const char *input_names[2] = { "leaf", "subleaf" };
-- 
2.34.1