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Commit e53c95e8 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
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KVM: x86: Encapsulate CPUID entries and metadata in struct 

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: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent c8629039
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Inline Side-by-side
Showing with 76 additions and 62 deletions
arch/x86/kvm/cpuid.c
View file @ e53c95e8
......@@ -287,13 +287,21 @@ static __always_inline void cpuid_mask(u32 *word, int wordnum)
*word &= boot_cpu_data.x86_capability[wordnum];
}
static struct kvm_cpuid_entry2 *do_host_cpuid(struct kvm_cpuid_entry2 *entry,
int *nent, int maxnent,
struct kvm_cpuid_array {
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)
{
if (*nent >= maxnent)
struct kvm_cpuid_entry2 *entry;
if (array->nent >= array->maxnent)
return NULL;
++*nent;
entry = &array->entries[array->nent++];
entry->function = function;
entry->index = index;
......@@ -325,9 +333,10 @@ static struct kvm_cpuid_entry2 *do_host_cpuid(struct kvm_cpuid_entry2 *entry,
return entry;
}
static int __do_cpuid_func_emulated(struct kvm_cpuid_entry2 *entry,
u32 func, int *nent, int maxnent)
static int __do_cpuid_func_emulated(struct kvm_cpuid_array *array, u32 func)
{
struct kvm_cpuid_entry2 *entry = &array->entries[array->nent];
entry->function = func;
entry->index = 0;
entry->flags = 0;
......@@ -335,17 +344,17 @@ static int __do_cpuid_func_emulated(struct kvm_cpuid_entry2 *entry,
switch (func) {
case 0:
entry->eax = 7;
++*nent;
++array->nent;
break;
case 1:
entry->ecx = F(MOVBE);
++*nent;
++array->nent;
break;
case 7:
entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
entry->eax = 0;
entry->ecx = F(RDPID);
++*nent;
++array->nent;
default:
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,
int *nent, int maxnent)
static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
{
struct kvm_cpuid_entry2 *entry;
int r, i, max_idx;
unsigned f_nx = is_efer_nx() ? F(NX) : 0;
#ifdef CONFIG_X86_64
......@@ -514,7 +523,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
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;
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;
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;
}
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
* zero, i.e. indicates an invalid entry.
*/
for (i = 1; entry[i - 1].eax & 0x1f; ++i) {
if (!do_host_cpuid(&entry[i], nent, maxnent, function, i))
for (i = 1; entry->eax & 0x1f; ++i) {
entry = do_host_cpuid(array, function, i);
if (!entry)
goto out;
}
break;
......@@ -566,10 +578,11 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
do_cpuid_7_mask(entry);
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;
do_cpuid_7_mask(&entry[i]);
do_cpuid_7_mask(entry);
}
break;
case 9:
......@@ -610,15 +623,13 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
case 0x1f:
case 0xb:
/*
* We filled in entry[0] for CPUID(EAX=<function>,
* ECX=00H) above. If its level type (ECX[15:8]) is
* zero, then the leaf is unimplemented, and we're
* done. Otherwise, continue to populate entries
* until the level type (ECX[15:8]) of the previously
* added entry is zero.
* Populate entries until the level type (ECX[15:8]) of the
* previous entry is zero. Note, CPUID EAX.{0x1f,0xb}.0 is
* the starting entry, filled by the primary do_host_cpuid().
*/
for (i = 1; entry[i - 1].ecx & 0xff00; ++i) {
if (!do_host_cpuid(&entry[i], nent, maxnent, function, i))
for (i = 1; entry->ecx & 0xff00; ++i) {
entry = do_host_cpuid(array, function, i);
if (!entry)
goto out;
}
break;
......@@ -633,24 +644,26 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
if (!supported)
break;
if (!do_host_cpuid(&entry[1], nent, maxnent, function, 1))
entry = do_host_cpuid(array, function, 1);
if (!entry)
goto out;
entry[1].eax &= kvm_cpuid_D_1_eax_x86_features;
cpuid_mask(&entry[1].eax, CPUID_D_1_EAX);
if (entry[1].eax & (F(XSAVES)|F(XSAVEC)))
entry[1].ebx = xstate_required_size(supported, true);
entry->eax &= kvm_cpuid_D_1_eax_x86_features;
cpuid_mask(&entry->eax, CPUID_D_1_EAX);
if (entry->eax & (F(XSAVES)|F(XSAVEC)))
entry->ebx = xstate_required_size(supported, true);
else
entry[1].ebx = 0;
entry->ebx = 0;
/* Saving XSS controlled state via XSAVES isn't supported. */
entry[1].ecx = 0;
entry[1].edx = 0;
entry->ecx = 0;
entry->edx = 0;
for (idx = 2, i = 2; idx < 64; ++idx) {
for (idx = 2; idx < 64; ++idx) {
if (!(supported & BIT_ULL(idx)))
continue;
if (!do_host_cpuid(&entry[i], nent, maxnent, function, idx))
entry = do_host_cpuid(array, function, idx);
if (!entry)
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
* save state size.
*/
if (WARN_ON_ONCE(!entry[i].eax || (entry[i].ecx & 1))) {
--*nent;
if (WARN_ON_ONCE(!entry->eax || (entry->ecx & 1))) {
--array->nent;
continue;
}
entry[i].ecx = 0;
entry[i].edx = 0;
++i;
entry->ecx = 0;
entry->edx = 0;
}
break;
}
......@@ -677,7 +689,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
break;
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;
}
break;
......@@ -802,22 +814,22 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
return r;
}
static int do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 func,
int *nent, int maxnent, unsigned int type)
static int do_cpuid_func(struct kvm_cpuid_array *array, u32 func,
unsigned int type)
{
if (*nent >= maxnent)
if (array->nent >= array->maxnent)
return -E2BIG;
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
static int get_cpuid_func(struct kvm_cpuid_entry2 *entries, u32 func,
int *nent, int maxnent, unsigned int type)
static int get_cpuid_func(struct kvm_cpuid_array *array, u32 func,
unsigned int type)
{
u32 limit;
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)
return 0;
r = do_cpuid_func(&entries[*nent], func, nent, maxnent, type);
r = do_cpuid_func(array, func, type);
if (r)
return r;
limit = entries[*nent - 1].eax;
limit = array->entries[array->nent - 1].eax;
for (func = func + 1; func <= limit; ++func) {
if (*nent >= maxnent)
if (array->nent >= array->maxnent)
return -E2BIG;
r = do_cpuid_func(&entries[*nent], func, nent, maxnent, type);
r = do_cpuid_func(array, func, type);
if (r)
break;
}
......@@ -878,8 +890,11 @@ int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
0, 0x80000000, CENTAUR_CPUID_SIGNATURE, KVM_CPUID_SIGNATURE,
};
struct kvm_cpuid_entry2 *cpuid_entries;
int nent = 0, r, i;
struct kvm_cpuid_array array = {
.nent = 0,
.maxnent = cpuid->nent,
};
int r, i;
if (cpuid->nent < 1)
return -E2BIG;
......@@ -889,25 +904,24 @@ int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
if (sanity_check_entries(entries, cpuid->nent, type))
return -EINVAL;
cpuid_entries = vzalloc(array_size(sizeof(struct kvm_cpuid_entry2),
array.entries = vzalloc(array_size(sizeof(struct kvm_cpuid_entry2),
cpuid->nent));
if (!cpuid_entries)
if (!array.entries)
return -ENOMEM;
for (i = 0; i < ARRAY_SIZE(funcs); i++) {
r = get_cpuid_func(cpuid_entries, funcs[i], &nent, cpuid->nent,
type);
r = get_cpuid_func(&array, funcs[i], type);
if (r)
goto out_free;
}
cpuid->nent = nent;
cpuid->nent = array.nent;
if (copy_to_user(entries, cpuid_entries,
nent * sizeof(struct kvm_cpuid_entry2)))
if (copy_to_user(entries, array.entries,
array.nent * sizeof(struct kvm_cpuid_entry2)))
r = -EFAULT;
out_free:
vfree(cpuid_entries);
vfree(array.entries);
return r;
}
......
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