| Message ID | 20200201185218.24473-17-sean.j.christopherson@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: x86: Introduce KVM cpu caps | expand |
Sean Christopherson <sean.j.christopherson@intel.com> writes: > 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. > > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> > --- > arch/x86/kvm/cpuid.c | 138 ++++++++++++++++++++++++------------------- > 1 file changed, 76 insertions(+), 62 deletions(-) > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > index d75d539da759..f9cfc69199f0 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -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, 2, 0); I'd change this to entry = do_host_cpuid(array, function, 0); to match other call sites. > + 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); Would it make sense to move 'if (array->nent >= array->maxnent)' check to __do_cpuid_func_emulated() to match do_host_cpuid()? > > - 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); do_cpuid_func() above is already doing 'if (array->nent >= array->maxnent)' check and returns -E2BIG when it fails, maybe the same check here in get_cpuid_func() is not needed? > 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; > } Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
On Fri, Feb 21, 2020 at 03:58:47PM +0100, Vitaly Kuznetsov wrote: > Sean Christopherson <sean.j.christopherson@intel.com> writes: > > > @@ -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, 2, 0); > > I'd change this to > entry = do_host_cpuid(array, function, 0); > > to match other call sites. Done. That did look weird, no idea why I decided to hardcode only this one. > > + if (!entry) > > 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); > > Would it make sense to move 'if (array->nent >= array->maxnent)' check > to __do_cpuid_func_emulated() to match do_host_cpuid()? I considered doing exactly that. IIRC, I opted not to because at this point in the series, the initial call to do_host_cpuid() is something like halfway down the massive __do_cpuid_func(), and eliminating the early check didn't feel quite right, e.g. there is a fair amount of unnecessary code that runs before hitting the first do_host_cpuid(). What if I add a patch towards the end of the series to move this check into __do_cpuid_func_emulated(), i.e. after __do_cpuid_func() has been trimmed down to size and the early check really is superfluous.
Sean Christopherson <sean.j.christopherson@intel.com> writes: > On Fri, Feb 21, 2020 at 03:58:47PM +0100, Vitaly Kuznetsov wrote: >> Sean Christopherson <sean.j.christopherson@intel.com> writes: >> > >> > + if (!entry) >> > 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); >> >> Would it make sense to move 'if (array->nent >= array->maxnent)' check >> to __do_cpuid_func_emulated() to match do_host_cpuid()? > > I considered doing exactly that. IIRC, I opted not to because at this > point in the series, the initial call to do_host_cpuid() is something like > halfway down the massive __do_cpuid_func(), and eliminating the early check > didn't feel quite right, e.g. there is a fair amount of unnecessary code > that runs before hitting the first do_host_cpuid(). > > What if I add a patch towards the end of the series to move this check into > __do_cpuid_func_emulated(), i.e. after __do_cpuid_func() has been trimmed > down to size and the early check really is superfluous. > Works for me, thanks!
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index d75d539da759..f9cfc69199f0 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -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, 2, 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; }
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. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> --- arch/x86/kvm/cpuid.c | 138 ++++++++++++++++++++++++------------------- 1 file changed, 76 insertions(+), 62 deletions(-)