From: Roger Pau Monne <roger.pau@citrix.com>
To: <xen-devel@lists.xenproject.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
Roger Pau Monne <roger.pau@citrix.com>,
Ian Jackson <iwj@xenproject.org>, Wei Liu <wl@xen.org>
Subject: [PATCH v2 16/21] libs/guest: make a cpu policy compatible with older Xen versions
Date: Tue, 13 Apr 2021 16:01:34 +0200 [thread overview]
Message-ID: <20210413140140.73690-17-roger.pau@citrix.com> (raw)
In-Reply-To: <20210413140140.73690-1-roger.pau@citrix.com>
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>
---
Changes since v1:
- Move comments and explicitly mention pre-4.14 Xen.
---
tools/include/xenctrl.h | 4 +++
tools/libs/guest/xg_cpuid_x86.c | 46 ++++++++++++++++++++++++++++-----
2 files changed, 43 insertions(+), 7 deletions(-)
diff --git a/tools/include/xenctrl.h b/tools/include/xenctrl.h
index c41d794683c..89a73fd6823 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 pre-4.14 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 6cfa4cb39d1..6486ac4c673 100644
--- a/tools/libs/guest/xg_cpuid_x86.c
+++ b/tools/libs/guest/xg_cpuid_x86.c
@@ -446,6 +446,7 @@ 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);
@@ -509,17 +510,14 @@ int xc_cpuid_apply_policy(xc_interface *xch, uint32_t domid, bool restore,
}
/*
- * Account for feature which have been disabled by default since Xen 4.13,
+ * Account for features which have been disabled by default since Xen 4.13,
* so migrated-in VM's don't risk seeing features disappearing.
*/
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);
+ *p = policy.cpuid;
}
if ( featureset )
@@ -1072,3 +1070,37 @@ 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;
+ }
+
+ /*
+ * 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;
+
+ if ( hvm )
+ policy->cpuid.feat.mpx = host->cpuid.feat.mpx;
+
+ out:
+ xc_cpu_policy_destroy(host);
+ return rc;
+}
--
2.30.1
next prev parent reply other threads:[~2021-04-13 14:03 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-13 14:01 [PATCH v2 00/21] libs/guest: new CPUID/MSR interface Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 01/21] libxl: don't ignore the return value from xc_cpuid_apply_policy Roger Pau Monne
2021-04-28 15:13 ` Anthony PERARD
2021-04-13 14:01 ` [PATCH v2 02/21] libs/guest: rename xc_get_cpu_policy_size to xc_cpu_policy_get_size Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 03/21] libs/guest: introduce xc_cpu_policy_t Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 04/21] libs/guest: introduce helper to fetch a system cpu policy Roger Pau Monne
2021-04-14 13:28 ` Jan Beulich
2021-04-13 14:01 ` [PATCH v2 05/21] libs/guest: introduce helper to fetch a domain " Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 06/21] libs/guest: introduce helper to serialize a " Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 07/21] tools: switch existing users of xc_get_{system,domain}_cpu_policy Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 08/21] libs/guest: introduce a helper to apply a cpu policy to a domain Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 09/21] libs/guest: allow fetching a specific CPUID leaf from a cpu policy Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 10/21] tests/cpu-policy: add sorted MSR test Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 11/21] libs/guest: allow fetching a specific MSR entry from a cpu policy Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 12/21] libs/guest: allow updating a cpu policy CPUID data Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 13/21] libs/guest: allow updating a cpu policy MSR data Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 14/21] libs/guest: introduce helper to check cpu policy compatibility Roger Pau Monne
2021-04-14 13:36 ` Jan Beulich
2021-04-22 8:22 ` Roger Pau Monné
2021-04-22 8:31 ` Jan Beulich
2021-04-13 14:01 ` [PATCH v2 15/21] libs/guest: obtain a compatible cpu policy from two input ones Roger Pau Monne
2021-04-14 13:49 ` Jan Beulich
2021-04-22 9:42 ` Roger Pau Monné
2021-04-22 9:58 ` Jan Beulich
2021-04-22 10:34 ` Roger Pau Monné
2021-04-22 10:48 ` Jan Beulich
2021-04-22 10:56 ` Roger Pau Monné
2021-04-22 11:05 ` Jan Beulich
2021-04-22 11:37 ` Roger Pau Monné
2021-04-22 11:42 ` Jan Beulich
2021-04-22 12:07 ` Roger Pau Monné
2021-04-22 12:08 ` Jan Beulich
2021-04-21 10:22 ` Wei Liu
2021-04-21 11:26 ` Roger Pau Monné
2021-04-21 16:42 ` Wei Liu
2021-04-13 14:01 ` Roger Pau Monne [this message]
2021-04-13 14:01 ` [PATCH v2 17/21] libs/guest: introduce helper set cpu topology in cpu policy Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 18/21] libs/guest: rework xc_cpuid_xend_policy Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 19/21] libs/guest: apply a featureset into a cpu policy Roger Pau Monne
2021-04-13 14:01 ` [PATCH v2 20/21] libs/{light,guest}: implement xc_cpuid_apply_policy in libxl Roger Pau Monne
2021-04-28 16:19 ` Anthony PERARD
2021-04-13 14:01 ` [PATCH v2 21/21] libs/guest: (re)move xc_cpu_policy_apply_cpuid Roger Pau Monne
2021-04-28 16:45 ` Anthony PERARD
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210413140140.73690-17-roger.pau@citrix.com \
--to=roger.pau@citrix.com \
--cc=andrew.cooper3@citrix.com \
--cc=iwj@xenproject.org \
--cc=wl@xen.org \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).