82 lines
2.5 KiB
Diff
82 lines
2.5 KiB
Diff
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# Commit 4c0ff6bd54b5a67f8f820f9ed0a89a79f1a26a1c
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# Date 2014-05-02 12:09:03 +0200
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# Author Jan Beulich <jbeulich@suse.com>
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# Committer Jan Beulich <jbeulich@suse.com>
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x86: fix guest CPUID handling
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The way XEN_DOMCTL_set_cpuid got handled so far allowed for surprises
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to the caller. With this set of operations
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- set leaf A (using array index 0)
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- set leaf B (using array index 1)
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- clear leaf A (clearing array index 0)
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- set leaf B (using array index 0)
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- clear leaf B (clearing array index 0)
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the entry for leaf B at array index 1 would still be in place, while
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the caller would expect it to be cleared.
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While looking at the use sites of d->arch.cpuid[] I also noticed that
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the allocation of the array needlessly uses the zeroing form - the
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relevant fields of the array elements get set in a loop immediately
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following the allocation.
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Signed-off-by: Jan Beulich <jbeulich@suse.com>
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Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
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Reviewed-by: Tim Deegan <tim@xen.org>
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--- a/xen/arch/x86/domain.c
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+++ b/xen/arch/x86/domain.c
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@@ -553,7 +553,7 @@ int arch_domain_create(struct domain *d,
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if ( !is_idle_domain(d) )
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{
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- d->arch.cpuids = xzalloc_array(cpuid_input_t, MAX_CPUID_INPUT);
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+ d->arch.cpuids = xmalloc_array(cpuid_input_t, MAX_CPUID_INPUT);
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rc = -ENOMEM;
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if ( d->arch.cpuids == NULL )
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goto fail;
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--- a/xen/arch/x86/domctl.c
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+++ b/xen/arch/x86/domctl.c
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@@ -920,7 +920,7 @@ long arch_do_domctl(
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case XEN_DOMCTL_set_cpuid:
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{
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xen_domctl_cpuid_t *ctl = &domctl->u.cpuid;
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- cpuid_input_t *cpuid = NULL;
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+ cpuid_input_t *cpuid, *unused = NULL;
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int i;
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for ( i = 0; i < MAX_CPUID_INPUT; i++ )
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@@ -928,7 +928,11 @@ long arch_do_domctl(
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cpuid = &d->arch.cpuids[i];
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if ( cpuid->input[0] == XEN_CPUID_INPUT_UNUSED )
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- break;
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+ {
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+ if ( !unused )
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+ unused = cpuid;
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+ continue;
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+ }
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if ( (cpuid->input[0] == ctl->input[0]) &&
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((cpuid->input[1] == XEN_CPUID_INPUT_UNUSED) ||
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@@ -936,15 +940,12 @@ long arch_do_domctl(
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break;
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}
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- if ( i == MAX_CPUID_INPUT )
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- {
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- ret = -ENOENT;
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- }
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+ if ( i < MAX_CPUID_INPUT )
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+ *cpuid = *ctl;
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+ else if ( unused )
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+ *unused = *ctl;
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else
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- {
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- memcpy(cpuid, ctl, sizeof(cpuid_input_t));
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- ret = 0;
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- }
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+ ret = -ENOENT;
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}
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break;
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