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KVM: selftests: Split out kvm_cpuid2_size() from allocate_kvm_cpuid2()

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Split out the computation of the effective size of a kvm_cpuid2 struct
from allocate_kvm_cpuid2(), and modify both to take an arbitrary number
of entries.  Future commits will add caching of a vCPU's CPUID model, and
will (a) be able to precisely size the entries array, and (b) will need
to know the effective size of the struct in order to copy to/from the
cache.

Expose the helpers so that the Hyper-V Features test can use them in the
(somewhat distant) future.  The Hyper-V test very, very subtly relies on
propagating CPUID info across vCPU instances, and will need to make a
copy of the previous vCPU's CPUID information when it switches to using
the per-vCPU cache.  Alternatively, KVM could provide helpers to
duplicate and/or copy a kvm_cpuid2 instance, but each is literally a
single line of code if the helpers are exposed, and it's not like the
size of kvm_cpuid2 is secret knowledge.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20220614200707.3315957-18-seanjc@google.com
This commit is contained in:
Sean Christopherson
2022-06-14 20:06:42 +00:00
parent 71bcb951c6
commit fc66963d7b
2 changed files with 30 additions and 41 deletions
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48
tools/testing/selftests/kvm/lib/x86_64/processor.c
View File

@@ -16,6 +16,8 @@
#define DEFAULT_CODE_SELECTOR 0x8
#define DEFAULT_DATA_SELECTOR 0x10
#define MAX_NR_CPUID_ENTRIES 100
vm_vaddr_t exception_handlers;
static void regs_dump(FILE *stream, struct kvm_regs *regs, uint8_t indent)
@@ -672,40 +674,6 @@ struct kvm_vcpu *vm_arch_vcpu_recreate(struct kvm_vm *vm, uint32_t vcpu_id)
return vcpu;
}
/*
* Allocate an instance of struct kvm_cpuid2
*
* Input Args: None
*
* Output Args: None
*
* Return: A pointer to the allocated struct. The caller is responsible
* for freeing this struct.
*
* Since kvm_cpuid2 uses a 0-length array to allow a the size of the
* array to be decided at allocation time, allocation is slightly
* complicated. This function uses a reasonable default length for
* the array and performs the appropriate allocation.
*/
static struct kvm_cpuid2 *allocate_kvm_cpuid2(void)
{
struct kvm_cpuid2 *cpuid;
int nent = 100;
size_t size;
size = sizeof(*cpuid);
size += nent * sizeof(struct kvm_cpuid_entry2);
cpuid = malloc(size);
if (!cpuid) {
perror("malloc");
abort();
}
cpuid->nent = nent;
return cpuid;
}
/*
* KVM Supported CPUID Get
*
@@ -725,7 +693,7 @@ struct kvm_cpuid2 *kvm_get_supported_cpuid(void)
if (cpuid)
return cpuid;
cpuid = allocate_kvm_cpuid2();
cpuid = allocate_kvm_cpuid2(MAX_NR_CPUID_ENTRIES);
kvm_fd = open_kvm_dev_path_or_exit();
kvm_ioctl(kvm_fd, KVM_GET_SUPPORTED_CPUID, cpuid);
@@ -781,7 +749,7 @@ struct kvm_cpuid2 *vcpu_get_cpuid(struct kvm_vcpu *vcpu)
int max_ent;
int rc = -1;
cpuid = allocate_kvm_cpuid2();
cpuid = allocate_kvm_cpuid2(MAX_NR_CPUID_ENTRIES);
max_ent = cpuid->nent;
for (cpuid->nent = 1; cpuid->nent <= max_ent; cpuid->nent++) {
@@ -1295,7 +1263,7 @@ struct kvm_cpuid2 *kvm_get_supported_hv_cpuid(void)
if (cpuid)
return cpuid;
cpuid = allocate_kvm_cpuid2();
cpuid = allocate_kvm_cpuid2(MAX_NR_CPUID_ENTRIES);
kvm_fd = open_kvm_dev_path_or_exit();
kvm_ioctl(kvm_fd, KVM_GET_SUPPORTED_HV_CPUID, cpuid);
@@ -1314,9 +1282,7 @@ void vcpu_set_hv_cpuid(struct kvm_vcpu *vcpu)
cpuid_sys = kvm_get_supported_cpuid();
cpuid_hv = kvm_get_supported_hv_cpuid();
cpuid_full = malloc(sizeof(*cpuid_full) +
(cpuid_sys->nent + cpuid_hv->nent) *
sizeof(struct kvm_cpuid_entry2));
cpuid_full = allocate_kvm_cpuid2(cpuid_sys->nent + cpuid_hv->nent);
if (!cpuid_full) {
perror("malloc");
abort();
@@ -1343,7 +1309,7 @@ struct kvm_cpuid2 *vcpu_get_supported_hv_cpuid(struct kvm_vcpu *vcpu)
{
static struct kvm_cpuid2 *cpuid;
cpuid = allocate_kvm_cpuid2();
cpuid = allocate_kvm_cpuid2(MAX_NR_CPUID_ENTRIES);
vcpu_ioctl(vcpu, KVM_GET_SUPPORTED_HV_CPUID, cpuid);