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>
Reviewed-by: Jan Beulich <jbeul...@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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