[PATCH v2 14/66] KVM: x86: Hoist loop counter and terminator to top of __do_cpuid_func()

Sean Christopherson
2020-03-03T00:01:56Z

Declare "i" and "max_idx" at the top of __do_cpuid_func() to consolidate
a handful of declarations in various case statements.

More importantly, establish the pattern of using max_idx instead of e.g.
entry->eax as the loop terminator in preparation for refactoring how
entry is handled in __do_cpuid_func().

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/cpuid.c | 37 +++++++++++++------------------------
1 file changed, 13 insertions(+), 24 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 1ae3b2502333..5044a595799f 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -439,7 +439,7 @@ static inline void do_cpuid_7_mask(struct kvm_cpuid_entry2 *entry)
static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
int *nent, int maxnent)
{
- int r;
+ int r, i, max_idx;
unsigned f_nx = is_efer_nx() ? F(NX) : 0;
#ifdef CONFIG_X86_64
unsigned f_gbpages = (kvm_x86_ops->get_lpage_level() == PT_PDPE_LEVEL)
@@ -535,20 +535,18 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
* may return different values. This forces us to get_cpu() before
* issuing the first command, and also to emulate this annoying behavior
* in kvm_emulate_cpuid() using KVM_CPUID_FLAG_STATE_READ_NEXT */
- case 2: {
- int t, times = entry->eax & 0xff;
-
+ case 2:
entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
- for (t = 1; t < times; ++t) {
- if (!do_host_cpuid(&entry[t], nent, maxnent, function, 0))
+
+ for (i = 1, max_idx = entry->eax & 0xff; i < max_idx; ++i) {
+ if (!do_host_cpuid(&entry[i], nent, maxnent, function, 0))
goto out;
}
break;
- }
/* functions 4 and 0x8000001d have additional index. */
case 4:
case 0x8000001d: {
- int i, cache_type;
+ int cache_type;

/* read more entries until cache_type is zero */
for (i = 1; ; ++i) {
@@ -568,19 +566,16 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
entry->edx = 0;
break;
/* function 7 has additional index. */
- case 7: {
- int i;
-
+ case 7:
do_cpuid_7_mask(entry);

- for (i = 1; i <= entry->eax; i++) {
+ for (i = 1, max_idx = entry->eax; i <= max_idx; i++) {
if (!do_host_cpuid(&entry[i], nent, maxnent, function, i))
goto out;

do_cpuid_7_mask(&entry[i]);
}
break;
- }
case 9:
break;
case 0xa: { /* Architectural Performance Monitoring */
@@ -617,9 +612,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
* thus they can be handled by common code.
*/
case 0x1f:
- case 0xb: {
- int i;
-
+ case 0xb:
/*
* We filled in entry[0] for CPUID(EAX=<function>,
* ECX=00H) above. If its level type (ECX[15:8]) is
@@ -633,9 +626,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
goto out;
}
break;
- }
case 0xd: {
- int idx, i;
+ int idx;
u64 supported = kvm_supported_xcr0();

entry->eax &= supported;
@@ -684,18 +676,15 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
break;
}
/* Intel PT */
- case 0x14: {
- int t, times = entry->eax;
-
+ case 0x14:
if (!f_intel_pt)
break;

- for (t = 1; t <= times; ++t) {
- if (!do_host_cpuid(&entry[t], nent, maxnent, function, t))
+ for (i = 1, max_idx = entry->eax; i <= max_idx; ++i) {
+ if (!do_host_cpuid(&entry[i], nent, maxnent, function, i))
goto out;
}
break;
- }
case KVM_CPUID_SIGNATURE: {
static const char signature[12] = "KVMKVMKVM\0\0";
const u32 *sigptr = (const u32 *)signature;
--
2.24.1