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.coop...@citrix.com>
---
CC: Jan Beulich <jbeul...@suse.com>
---
xen/arch/x86/cpu/common.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
index b48ce58..ba42ac0 100644
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -49,8 +49,24 @@ static unsigned int __cpuinitdata cleared_caps[NCAPINTS];
void __init setup_clear_cpu_cap(unsigned int cap)
{
+ const struct tagged_featureset *dfs;
+ unsigned int i;
+
+ if ( test_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 < ARRAY_SIZE(dfs->fs); ++i ) {
+ cleared_caps[i] |= dfs->fs[i];
+ boot_cpu_data.x86_capability[i] &= ~dfs->fs[i];
+ }
}
static void default_init(struct cpuinfo_x86 * c)
--
2.1.4
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