[PATCH v2 09/66] KVM: x86: Refactor CPUID 0xD.N sub-leaf entry creation

Sean Christopherson
2020-03-03T00:00:18Z

Increment the number of CPUID entries immediately after do_host_cpuid()
in preparation for moving the logic into do_host_cpuid(). Handle the
rare/impossible case of encountering a bogus sub-leaf by decrementing
the number entries on failure.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/cpuid.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 424dde41cb5d..6e1685a16cca 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -677,6 +677,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
goto out;

do_host_cpuid(&entry[i], function, idx);
+ ++*nent;

/*
* The @supported check above should have filtered out
@@ -685,12 +686,13 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
* reach this point, and they should have a non-zero
* save state size.
*/
- if (WARN_ON_ONCE(!entry[i].eax || (entry[i].ecx & 1)))
+ if (WARN_ON_ONCE(!entry[i].eax || (entry[i].ecx & 1))) {
+ --*nent;
continue;
+ }

entry[i].ecx = 0;
entry[i].edx = 0;
- ++*nent;
++i;
}
break;
--
2.24.1