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From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Xen-devel <xen-devel@lists.xen.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Subject: [PATCH v5 04/21] xen/x86: Clear dependent features when clearing a cpu cap
Date: Thu, 7 Apr 2016 12:57:09 +0100	[thread overview]
Message-ID: <1460030246-30153-5-git-send-email-andrew.cooper3@citrix.com> (raw)
In-Reply-To: <1460030246-30153-1-git-send-email-andrew.cooper3@citrix.com>

When clearing a cpu cap, clear all dependent features.  This avoids having a
featureset with intermediate features disabled, but leaf features enabled.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <JBeulich@suse.com>
---
v3:
 * Style fixes.  Use __test_and_set_bit()
---
 xen/arch/x86/cpu/common.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
index d302272..0942b44 100644
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -53,8 +53,22 @@ static unsigned int cleared_caps[NCAPINTS];
 
 void __init setup_clear_cpu_cap(unsigned int cap)
 {
+	const uint32_t *dfs;
+	unsigned int i;
+
+	if (__test_and_set_bit(cap, cleared_caps))
+		return;
+
 	__clear_bit(cap, boot_cpu_data.x86_capability);
-	__set_bit(cap, cleared_caps);
+	dfs = lookup_deep_deps(cap);
+
+	if (!dfs)
+		return;
+
+	for (i = 0; i < FSCAPINTS; ++i) {
+		cleared_caps[i] |= dfs[i];
+		boot_cpu_data.x86_capability[i] &= ~dfs[i];
+	}
 }
 
 static void default_init(struct cpuinfo_x86 * c)
-- 
2.1.4


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  parent reply	other threads:[~2016-04-07 11:57 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-07 11:57 [PATCH v5 00/21] x86: Improvements to cpuid handling for guests Andrew Cooper
2016-04-07 11:57 ` [PATCH v5 01/21] xen/x86: Annotate VM applicability in featureset Andrew Cooper
2016-04-07 23:01   ` Jan Beulich
2016-04-07 11:57 ` [PATCH v5 02/21] xen/x86: Calculate maximum host and guest featuresets Andrew Cooper
2016-04-07 23:04   ` Jan Beulich
2016-04-07 11:57 ` [PATCH v5 03/21] xen/x86: Generate deep dependencies of features Andrew Cooper
2016-04-07 23:18   ` Jan Beulich
2016-04-07 23:36     ` Andrew Cooper
2016-04-08 15:17       ` Jan Beulich
2016-04-08 15:18         ` Andrew Cooper
2016-04-07 11:57 ` Andrew Cooper [this message]
2016-04-08 15:36   ` [PATCH v5 04/21] xen/x86: Clear dependent features when clearing a cpu cap Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 05/21] xen/x86: Improve disabling of features which have dependencies Andrew Cooper
2016-04-08 15:04   ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 06/21] xen/x86: Improvements to in-hypervisor cpuid sanity checks Andrew Cooper
2016-04-08 16:10   ` Konrad Rzeszutek Wilk
2016-04-08 18:06   ` Jan Beulich
2016-04-07 11:57 ` [PATCH v5 07/21] x86/cpu: Move set_cpumask() calls into c_early_init() Andrew Cooper
2016-04-08 18:09   ` Jan Beulich
2016-04-07 11:57 ` [PATCH v5 08/21] x86/cpu: Sysctl and common infrastructure for levelling context switching Andrew Cooper
2016-04-07 16:54   ` Daniel De Graaf
2016-04-08 16:12   ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 09/21] x86/cpu: Rework AMD masking MSR setup Andrew Cooper
2016-04-08 16:13   ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 10/21] x86/cpu: Rework Intel masking/faulting setup Andrew Cooper
2016-04-08 16:14   ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 11/21] x86/cpu: Context switch cpuid masks and faulting state in context_switch() Andrew Cooper
2016-04-08 16:15   ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 12/21] x86/pv: Provide custom cpumasks for PV domains Andrew Cooper
2016-04-08 16:17   ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 13/21] x86/domctl: Update PV domain cpumasks when setting cpuid policy Andrew Cooper
2016-04-08 16:26   ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 14/21] xen+tools: Export maximum host and guest cpu featuresets via SYSCTL Andrew Cooper
2016-04-07 16:54   ` Daniel De Graaf
2016-04-08 16:32   ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 15/21] tools/libxc: Modify bitmap operations to take void pointers Andrew Cooper
2016-04-07 13:00   ` Wei Liu
2016-04-08 16:34   ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 16/21] tools/libxc: Use public/featureset.h for cpuid policy generation Andrew Cooper
2016-04-08 16:37   ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 17/21] tools/libxc: Expose the automatically generated cpu featuremask information Andrew Cooper
2016-04-08 16:38   ` Konrad Rzeszutek Wilk
2016-04-07 11:57 ` [PATCH v5 18/21] tools: Utility for dealing with featuresets Andrew Cooper
2016-04-07 11:57 ` [PATCH v5 19/21] tools/libxc: Wire a featureset through to cpuid policy logic Andrew Cooper
2016-04-07 11:57 ` [PATCH v5 20/21] tools/libxc: Use featuresets rather than guesswork Andrew Cooper
2016-04-07 11:57 ` [PATCH v5 21/21] tools/libxc: Calculate xstate cpuid leaf from guest information Andrew Cooper
2016-04-07 12:58   ` Wei Liu
2016-04-08 21:00   ` Jan Beulich
2016-04-08 21:45     ` Andrew Cooper
2016-04-08 22:38       ` Jan Beulich

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