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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging] tools/libx[cl]: Move processing loop down into xc_cpuid_set()
commit 585c7f4317987b4e92a381d6178be238be4c9653
Author: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Fri Jun 12 14:07:10 2020 +0100
Commit: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Wed Jun 17 13:54:12 2020 +0100
tools/libx[cl]: Move processing loop down into xc_cpuid_set()
Currently, libxl__cpuid_legacy() passes each element of the policy list to
xc_cpuid_set() individually. This is wasteful both in terms of the number
of
hypercalls made, and the quantity of repeated merging/auditing work
performed
by Xen.
Move the loop processing down into xc_cpuid_set(), which allows us to do one
set of hypercalls, rather than one per list entry.
In xc_cpuid_set(), obtain the full host, guest max and current policies to
begin with, and loop over the xend array, processing one leaf at a time.
Replace the linear search with a binary search, seeing as the serialised
leaves are sorted.
No change in behaviour from the guests point of view.
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
Acked-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Release-acked-by: Paul Durrant <paul@xxxxxxx>
---
tools/libxc/xc_cpuid_x86.c | 159 +++++++++++++++++++++++++++------------------
tools/libxl/libxl_cpuid.c | 4 +-
2 files changed, 95 insertions(+), 68 deletions(-)
diff --git a/tools/libxc/xc_cpuid_x86.c b/tools/libxc/xc_cpuid_x86.c
index edc2ad9b47..548762e7b4 100644
--- a/tools/libxc/xc_cpuid_x86.c
+++ b/tools/libxc/xc_cpuid_x86.c
@@ -38,8 +38,6 @@ enum {
#define bitmaskof(idx) (1u << ((idx) & 31))
#define featureword_of(idx) ((idx) >> 5)
-#define clear_feature(idx, dst) ((dst) &= ~bitmaskof(idx))
-#define set_feature(idx, dst) ((dst) |= bitmaskof(idx))
int xc_get_cpu_levelling_caps(xc_interface *xch, uint32_t *caps)
{
@@ -259,15 +257,42 @@ int xc_set_domain_cpu_policy(xc_interface *xch, uint32_t
domid,
return ret;
}
+static int compare_leaves(const void *l, const void *r)
+{
+ const xen_cpuid_leaf_t *lhs = l;
+ const xen_cpuid_leaf_t *rhs = r;
+
+ if ( lhs->leaf != rhs->leaf )
+ return lhs->leaf < rhs->leaf ? -1 : 1;
+
+ if ( lhs->subleaf != rhs->subleaf )
+ return lhs->subleaf < rhs->subleaf ? -1 : 1;
+
+ return 0;
+}
+
+static xen_cpuid_leaf_t *find_leaf(
+ xen_cpuid_leaf_t *leaves, unsigned int nr_leaves,
+ const struct xc_xend_cpuid *xend)
+{
+ const xen_cpuid_leaf_t key = { xend->leaf, xend->subleaf };
+
+ return bsearch(&key, leaves, nr_leaves, sizeof(*leaves), compare_leaves);
+}
+
int xc_cpuid_set(
xc_interface *xch, uint32_t domid, const struct xc_xend_cpuid *xend)
{
int rc;
- unsigned int i, j, regs[4] = {}, polregs[4] = {};
xc_dominfo_t di;
- xen_cpuid_leaf_t *leaves = NULL;
- unsigned int nr_leaves, policy_leaves, nr_msrs;
+ unsigned int nr_leaves, nr_msrs;
uint32_t err_leaf = -1, err_subleaf = -1, err_msr = -1;
+ /*
+ * Three full policies. The host, domain max, and domain current for the
+ * domain type.
+ */
+ xen_cpuid_leaf_t *host = NULL, *max = NULL, *cur = NULL;
+ unsigned int nr_host, nr_max, nr_cur;
if ( xc_domain_getinfo(xch, domid, 1, &di) != 1 ||
di.domid != domid )
@@ -286,99 +311,101 @@ int xc_cpuid_set(
}
rc = -ENOMEM;
- if ( (leaves = calloc(nr_leaves, sizeof(*leaves))) == NULL )
+ if ( (host = calloc(nr_leaves, sizeof(*host))) == NULL ||
+ (max = calloc(nr_leaves, sizeof(*max))) == NULL ||
+ (cur = calloc(nr_leaves, sizeof(*cur))) == NULL )
{
ERROR("Unable to allocate memory for %u CPUID leaves", nr_leaves);
goto fail;
}
+ /* Get the domain's current policy. */
+ nr_msrs = 0;
+ nr_cur = nr_leaves;
+ rc = xc_get_domain_cpu_policy(xch, domid, &nr_cur, cur, &nr_msrs, NULL);
+ if ( rc )
+ {
+ PERROR("Failed to obtain d%d current policy", domid);
+ rc = -errno;
+ goto fail;
+ }
+
/* Get the domain's max policy. */
nr_msrs = 0;
- policy_leaves = nr_leaves;
+ nr_max = nr_leaves;
rc = xc_get_system_cpu_policy(xch, di.hvm ? XEN_SYSCTL_cpu_policy_hvm_max
: XEN_SYSCTL_cpu_policy_pv_max,
- &policy_leaves, leaves, &nr_msrs, NULL);
+ &nr_max, max, &nr_msrs, NULL);
if ( rc )
{
PERROR("Failed to obtain %s max policy", di.hvm ? "hvm" : "pv");
rc = -errno;
goto fail;
}
- for ( i = 0; i < policy_leaves; ++i )
- if ( leaves[i].leaf == xend->leaf &&
- leaves[i].subleaf == xend->subleaf )
- {
- polregs[0] = leaves[i].a;
- polregs[1] = leaves[i].b;
- polregs[2] = leaves[i].c;
- polregs[3] = leaves[i].d;
- break;
- }
/* Get the host policy. */
nr_msrs = 0;
- policy_leaves = nr_leaves;
+ nr_host = nr_leaves;
rc = xc_get_system_cpu_policy(xch, XEN_SYSCTL_cpu_policy_host,
- &policy_leaves, leaves, &nr_msrs, NULL);
+ &nr_host, host, &nr_msrs, NULL);
if ( rc )
{
PERROR("Failed to obtain host policy");
rc = -errno;
goto fail;
}
- for ( i = 0; i < policy_leaves; ++i )
- if ( leaves[i].leaf == xend->leaf &&
- leaves[i].subleaf == xend->subleaf )
- {
- regs[0] = leaves[i].a;
- regs[1] = leaves[i].b;
- regs[2] = leaves[i].c;
- regs[3] = leaves[i].d;
- break;
- }
- for ( i = 0; i < 4; i++ )
+ rc = -EINVAL;
+ for ( ; xend->leaf != XEN_CPUID_INPUT_UNUSED; ++xend )
{
- if ( xend->policy[i] == NULL )
+ xen_cpuid_leaf_t *cur_leaf = find_leaf(cur, nr_cur, xend);
+ const xen_cpuid_leaf_t *max_leaf = find_leaf(max, nr_max, xend);
+ const xen_cpuid_leaf_t *host_leaf = find_leaf(host, nr_host, xend);
+
+ if ( cur_leaf == NULL || max_leaf == NULL || host_leaf == NULL )
{
- regs[i] = polregs[i];
- continue;
+ ERROR("Missing leaf %#x, subleaf %#x", xend->leaf, xend->subleaf);
+ goto fail;
}
- /*
- * Notes for following this algorithm:
- *
- * While it will accept any leaf data, it only makes sense to use on
- * feature leaves. regs[] initially contains the host values. This,
- * with the fall-through chain, is how the 's' and 'k' options work.
- */
- for ( j = 0; j < 32; j++ )
+ for ( unsigned int i = 0; i < ARRAY_SIZE(xend->policy); i++ )
{
- unsigned char val = !!((regs[i] & (1U << (31 - j))));
- unsigned char polval = !!((polregs[i] & (1U << (31 - j))));
-
- rc = -EINVAL;
- if ( !strchr("10xks", xend->policy[i][j]) )
- goto fail;
-
- if ( xend->policy[i][j] == '1' )
- val = 1;
- else if ( xend->policy[i][j] == '0' )
- val = 0;
- else if ( xend->policy[i][j] == 'x' )
- val = polval;
-
- if ( val )
- set_feature(31 - j, regs[i]);
- else
- clear_feature(31 - j, regs[i]);
+ uint32_t *cur_reg = &cur_leaf->a + i;
+ const uint32_t *max_reg = &max_leaf->a + i;
+ const uint32_t *host_reg = &host_leaf->a + i;
+
+ if ( xend->policy[i] == NULL )
+ continue;
+
+ for ( unsigned int j = 0; j < 32; j++ )
+ {
+ bool val;
+
+ if ( xend->policy[i][j] == '1' )
+ val = true;
+ else if ( xend->policy[i][j] == '0' )
+ val = false;
+ else if ( xend->policy[i][j] == 'x' )
+ val = test_bit(31 - j, max_reg);
+ else if ( xend->policy[i][j] == 'k' ||
+ xend->policy[i][j] == 's' )
+ val = test_bit(31 - j, host_reg);
+ else
+ {
+ ERROR("Bad character '%c' in policy[%d] string '%s'",
+ xend->policy[i][j], i, xend->policy[i]);
+ goto fail;
+ }
+
+ clear_bit(31 - j, cur_reg);
+ if ( val )
+ set_bit(31 - j, cur_reg);
+ }
}
}
- /* Feed the transformed leaf back up to Xen. */
- leaves[0] = (xen_cpuid_leaf_t){ xend->leaf, xend->subleaf,
- regs[0], regs[1], regs[2], regs[3] };
- rc = xc_set_domain_cpu_policy(xch, domid, 1, leaves, 0, NULL,
+ /* Feed the transformed currrent policy back up to Xen. */
+ rc = xc_set_domain_cpu_policy(xch, domid, nr_cur, cur, 0, NULL,
&err_leaf, &err_subleaf, &err_msr);
if ( rc )
{
@@ -391,7 +418,9 @@ int xc_cpuid_set(
/* Success! */
fail:
- free(leaves);
+ free(cur);
+ free(max);
+ free(host);
return rc;
}
diff --git a/tools/libxl/libxl_cpuid.c b/tools/libxl/libxl_cpuid.c
index e001cbcd4f..6f7cf2054e 100644
--- a/tools/libxl/libxl_cpuid.c
+++ b/tools/libxl/libxl_cpuid.c
@@ -420,7 +420,6 @@ void libxl__cpuid_legacy(libxl_ctx *ctx, uint32_t domid,
libxl_domain_build_info *info)
{
libxl_cpuid_policy_list cpuid = info->cpuid;
- int i;
bool pae = true;
/*
@@ -441,8 +440,7 @@ void libxl__cpuid_legacy(libxl_ctx *ctx, uint32_t domid,
if (!cpuid)
return;
- for (i = 0; cpuid[i].input[0] != XEN_CPUID_INPUT_UNUSED; i++)
- xc_cpuid_set(ctx->xch, domid, &cpuid[i]);
+ xc_cpuid_set(ctx->xch, domid, info->cpuid);
}
static const char *input_names[2] = { "leaf", "subleaf" };
--
generated by git-patchbot for /home/xen/git/xen.git#staging
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