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KVM: x86: Encapsulate CPUID entries and metadata in struct

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Add a struct to hold the array of CPUID entries and its associated
metadata when handling KVM_GET_SUPPORTED_CPUID.  Lookup and provide
the correct entry in do_host_cpuid(), which eliminates the majority of
array indexing shenanigans, e.g. entries[i -1], and generally makes the
code more readable.  The last array indexing holdout is kvm_get_cpuid(),
which can't really be avoided without throwing the baby out with the
bathwater.

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2020-03-02 15:56:19 -08:00 committed by Paolo Bonzini
parent c862903963
commit e53c95e8d4
1 changed files with 76 additions and 62 deletions
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138
arch/x86/kvm/cpuid.c
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@ -287,13 +287,21 @@ static __always_inline void cpuid_mask(u32 *word, int wordnum)
*word &= boot_cpu_data.x86_capability[wordnum]; *word &= boot_cpu_data.x86_capability[wordnum];
} }
static struct kvm_cpuid_entry2 *do_host_cpuid(struct kvm_cpuid_entry2 *entry, struct kvm_cpuid_array {
int *nent, int maxnent, struct kvm_cpuid_entry2 *entries;
const int maxnent;
int nent;
};
static struct kvm_cpuid_entry2 *do_host_cpuid(struct kvm_cpuid_array *array,
u32 function, u32 index) u32 function, u32 index)
{ {
if (*nent >= maxnent) struct kvm_cpuid_entry2 *entry;
if (array->nent >= array->maxnent)
return NULL; return NULL;
++*nent;
entry = &array->entries[array->nent++];
entry->function = function; entry->function = function;
entry->index = index; entry->index = index;
@ -325,9 +333,10 @@ static struct kvm_cpuid_entry2 *do_host_cpuid(struct kvm_cpuid_entry2 *entry,
return entry; return entry;
} }
static int __do_cpuid_func_emulated(struct kvm_cpuid_entry2 *entry, static int __do_cpuid_func_emulated(struct kvm_cpuid_array *array, u32 func)
u32 func, int *nent, int maxnent)
{ {
struct kvm_cpuid_entry2 *entry = &array->entries[array->nent];
entry->function = func; entry->function = func;
entry->index = 0; entry->index = 0;
entry->flags = 0; entry->flags = 0;
@ -335,17 +344,17 @@ static int __do_cpuid_func_emulated(struct kvm_cpuid_entry2 *entry,
switch (func) { switch (func) {
case 0: case 0:
entry->eax = 7; entry->eax = 7;
++*nent; ++array->nent;
break; break;
case 1: case 1:
entry->ecx = F(MOVBE); entry->ecx = F(MOVBE);
++*nent; ++array->nent;
break; break;
case 7: case 7:
entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX; entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
entry->eax = 0; entry->eax = 0;
entry->ecx = F(RDPID); entry->ecx = F(RDPID);
++*nent; ++array->nent;
default: default:
break; break;
} }
@ -436,9 +445,9 @@ 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, static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
int *nent, int maxnent)
{ {
struct kvm_cpuid_entry2 *entry;
int r, i, max_idx; int r, i, max_idx;
unsigned f_nx = is_efer_nx() ? F(NX) : 0; unsigned f_nx = is_efer_nx() ? F(NX) : 0;
#ifdef CONFIG_X86_64 #ifdef CONFIG_X86_64
@ -514,7 +523,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
r = -E2BIG; r = -E2BIG;
if (WARN_ON(!do_host_cpuid(entry, nent, maxnent, function, 0))) entry = do_host_cpuid(array, function, 0);
if (WARN_ON(!entry))
goto out; goto out;
switch (function) { switch (function) {
@ -539,7 +549,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT; entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
for (i = 1, max_idx = entry->eax & 0xff; i < max_idx; ++i) { for (i = 1, max_idx = entry->eax & 0xff; i < max_idx; ++i) {
if (!do_host_cpuid(&entry[i], nent, maxnent, function, 0)) entry = do_host_cpuid(array, function, 0);
if (!entry)
goto out; goto out;
} }
break; break;
@ -550,8 +561,9 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
* Read entries until the cache type in the previous entry is * Read entries until the cache type in the previous entry is
* zero, i.e. indicates an invalid entry. * zero, i.e. indicates an invalid entry.
*/ */
for (i = 1; entry[i - 1].eax & 0x1f; ++i) { for (i = 1; entry->eax & 0x1f; ++i) {
if (!do_host_cpuid(&entry[i], nent, maxnent, function, i)) entry = do_host_cpuid(array, function, i);
if (!entry)
goto out; goto out;
} }
break; break;
@ -566,10 +578,11 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
do_cpuid_7_mask(entry); do_cpuid_7_mask(entry);
for (i = 1, max_idx = entry->eax; i <= max_idx; i++) { for (i = 1, max_idx = entry->eax; i <= max_idx; i++) {
if (!do_host_cpuid(&entry[i], nent, maxnent, function, i)) entry = do_host_cpuid(array, function, i);
if (!entry)
goto out; goto out;
do_cpuid_7_mask(&entry[i]); do_cpuid_7_mask(entry);
} }
break; break;
case 9: case 9:
@ -610,15 +623,13 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
case 0x1f: case 0x1f:
case 0xb: case 0xb:
/* /*
* We filled in entry[0] for CPUID(EAX=<function>, * Populate entries until the level type (ECX[15:8]) of the
* ECX=00H) above. If its level type (ECX[15:8]) is * previous entry is zero. Note, CPUID EAX.{0x1f,0xb}.0 is
* zero, then the leaf is unimplemented, and we're * the starting entry, filled by the primary do_host_cpuid().
* done. Otherwise, continue to populate entries
* until the level type (ECX[15:8]) of the previously
* added entry is zero.
*/ */
for (i = 1; entry[i - 1].ecx & 0xff00; ++i) { for (i = 1; entry->ecx & 0xff00; ++i) {
if (!do_host_cpuid(&entry[i], nent, maxnent, function, i)) entry = do_host_cpuid(array, function, i);
if (!entry)
goto out; goto out;
} }
break; break;
@ -633,24 +644,26 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
if (!supported) if (!supported)
break; break;
if (!do_host_cpuid(&entry[1], nent, maxnent, function, 1)) entry = do_host_cpuid(array, function, 1);
if (!entry)
goto out; goto out;
entry[1].eax &= kvm_cpuid_D_1_eax_x86_features; entry->eax &= kvm_cpuid_D_1_eax_x86_features;
cpuid_mask(&entry[1].eax, CPUID_D_1_EAX); cpuid_mask(&entry->eax, CPUID_D_1_EAX);
if (entry[1].eax & (F(XSAVES)|F(XSAVEC))) if (entry->eax & (F(XSAVES)|F(XSAVEC)))
entry[1].ebx = xstate_required_size(supported, true); entry->ebx = xstate_required_size(supported, true);
else else
entry[1].ebx = 0; entry->ebx = 0;
/* Saving XSS controlled state via XSAVES isn't supported. */ /* Saving XSS controlled state via XSAVES isn't supported. */
entry[1].ecx = 0; entry->ecx = 0;
entry[1].edx = 0; entry->edx = 0;
for (idx = 2, i = 2; idx < 64; ++idx) { for (idx = 2; idx < 64; ++idx) {
if (!(supported & BIT_ULL(idx))) if (!(supported & BIT_ULL(idx)))
continue; continue;
if (!do_host_cpuid(&entry[i], nent, maxnent, function, idx)) entry = do_host_cpuid(array, function, idx);
if (!entry)
goto out; goto out;
/* /*
@ -660,14 +673,13 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
* reach this point, and they should have a non-zero * reach this point, and they should have a non-zero
* save state size. * save state size.
*/ */
if (WARN_ON_ONCE(!entry[i].eax || (entry[i].ecx & 1))) { if (WARN_ON_ONCE(!entry->eax || (entry->ecx & 1))) {
--*nent; --array->nent;
continue; continue;
} }
entry[i].ecx = 0; entry->ecx = 0;
entry[i].edx = 0; entry->edx = 0;
++i;
} }
break; break;
} }
@ -677,7 +689,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
break; break;
for (i = 1, max_idx = entry->eax; i <= max_idx; ++i) { for (i = 1, max_idx = entry->eax; i <= max_idx; ++i) {
if (!do_host_cpuid(&entry[i], nent, maxnent, function, i)) if (!do_host_cpuid(array, function, i))
goto out; goto out;
} }
break; break;
@ -802,22 +814,22 @@ out:
return r; return r;
} }
static int do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 func, static int do_cpuid_func(struct kvm_cpuid_array *array, u32 func,
int *nent, int maxnent, unsigned int type) unsigned int type)
{ {
if (*nent >= maxnent) if (array->nent >= array->maxnent)
return -E2BIG; return -E2BIG;
if (type == KVM_GET_EMULATED_CPUID) if (type == KVM_GET_EMULATED_CPUID)
return __do_cpuid_func_emulated(entry, func, nent, maxnent); return __do_cpuid_func_emulated(array, func);
return __do_cpuid_func(entry, func, nent, maxnent); return __do_cpuid_func(array, func);
} }
#define CENTAUR_CPUID_SIGNATURE 0xC0000000 #define CENTAUR_CPUID_SIGNATURE 0xC0000000
static int get_cpuid_func(struct kvm_cpuid_entry2 *entries, u32 func, static int get_cpuid_func(struct kvm_cpuid_array *array, u32 func,
int *nent, int maxnent, unsigned int type) unsigned int type)
{ {
u32 limit; u32 limit;
int r; int r;
@ -826,16 +838,16 @@ static int get_cpuid_func(struct kvm_cpuid_entry2 *entries, u32 func,
boot_cpu_data.x86_vendor != X86_VENDOR_CENTAUR) boot_cpu_data.x86_vendor != X86_VENDOR_CENTAUR)
return 0; return 0;
r = do_cpuid_func(&entries[*nent], func, nent, maxnent, type); r = do_cpuid_func(array, func, type);
if (r) if (r)
return r; return r;
limit = entries[*nent - 1].eax; limit = array->entries[array->nent - 1].eax;
for (func = func + 1; func <= limit; ++func) { for (func = func + 1; func <= limit; ++func) {
if (*nent >= maxnent) if (array->nent >= array->maxnent)
return -E2BIG; return -E2BIG;
r = do_cpuid_func(&entries[*nent], func, nent, maxnent, type); r = do_cpuid_func(array, func, type);
if (r) if (r)
break; break;
} }
@ -878,8 +890,11 @@ int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
0, 0x80000000, CENTAUR_CPUID_SIGNATURE, KVM_CPUID_SIGNATURE, 0, 0x80000000, CENTAUR_CPUID_SIGNATURE, KVM_CPUID_SIGNATURE,
}; };
struct kvm_cpuid_entry2 *cpuid_entries; struct kvm_cpuid_array array = {
int nent = 0, r, i; .nent = 0,
.maxnent = cpuid->nent,
};
int r, i;
if (cpuid->nent < 1) if (cpuid->nent < 1)
return -E2BIG; return -E2BIG;
@ -889,25 +904,24 @@ int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
if (sanity_check_entries(entries, cpuid->nent, type)) if (sanity_check_entries(entries, cpuid->nent, type))
return -EINVAL; return -EINVAL;
cpuid_entries = vzalloc(array_size(sizeof(struct kvm_cpuid_entry2), array.entries = vzalloc(array_size(sizeof(struct kvm_cpuid_entry2),
cpuid->nent)); cpuid->nent));
if (!cpuid_entries) if (!array.entries)
return -ENOMEM; return -ENOMEM;
for (i = 0; i < ARRAY_SIZE(funcs); i++) { for (i = 0; i < ARRAY_SIZE(funcs); i++) {
r = get_cpuid_func(cpuid_entries, funcs[i], &nent, cpuid->nent, r = get_cpuid_func(&array, funcs[i], type);
type);
if (r) if (r)
goto out_free; goto out_free;
} }
cpuid->nent = nent; cpuid->nent = array.nent;
if (copy_to_user(entries, cpuid_entries, if (copy_to_user(entries, array.entries,
nent * sizeof(struct kvm_cpuid_entry2))) array.nent * sizeof(struct kvm_cpuid_entry2)))
r = -EFAULT; r = -EFAULT;
out_free: out_free:
vfree(cpuid_entries); vfree(array.entries);
return r; return r;
} }