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Message-Id: <20220614200707.3315957-18-seanjc@google.com>
Date: Tue, 14 Jun 2022 20:06:42 +0000
From: Sean Christopherson <seanjc@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
Sean Christopherson <seanjc@...gle.com>,
Jim Mattson <jmattson@...gle.com>
Subject: [PATCH v2 17/42] KVM: selftests: Split out kvm_cpuid2_size() from allocate_kvm_cpuid2()
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@...gle.com>
---
.../selftests/kvm/include/x86_64/processor.h | 23 +++++++++
.../selftests/kvm/lib/x86_64/processor.c | 48 +++----------------
2 files changed, 30 insertions(+), 41 deletions(-)
diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index f5fa7d2e44a6..002ed02cc2ef 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -593,6 +593,29 @@ static inline bool kvm_cpu_has(struct kvm_x86_cpu_feature feature)
return kvm_cpuid_has(kvm_get_supported_cpuid(), feature);
}
+static inline size_t kvm_cpuid2_size(int nr_entries)
+{
+ return sizeof(struct kvm_cpuid2) +
+ sizeof(struct kvm_cpuid_entry2) * nr_entries;
+}
+
+/*
+ * Allocate a "struct kvm_cpuid2* instance, with the 0-length arrary of
+ * entries sized to hold @nr_entries. The caller is responsible for freeing
+ * the struct.
+ */
+static inline struct kvm_cpuid2 *allocate_kvm_cpuid2(int nr_entries)
+{
+ struct kvm_cpuid2 *cpuid;
+
+ cpuid = malloc(kvm_cpuid2_size(nr_entries));
+ TEST_ASSERT(cpuid, "-ENOMEM when allocating kvm_cpuid2");
+
+ cpuid->nent = nr_entries;
+
+ return cpuid;
+}
+
struct kvm_cpuid2 *vcpu_get_cpuid(struct kvm_vcpu *vcpu);
static inline int __vcpu_set_cpuid(struct kvm_vcpu *vcpu,
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index 7666f24a145a..e9a2c606c6c3 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -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++) {
@@ -1278,7 +1246,7 @@ 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);
@@ -1297,9 +1265,7 @@ 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();
@@ -1326,7 +1292,7 @@ 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);
--
2.36.1.476.g0c4daa206d-goog
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