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Subject[PATCH] KVM: Use previously computed array_size()
Date
array_size() is used in alloc calls to compute the allocation
size. Next, "raw" multiplication is used to compute the size
for copy_from_user(). The patch removes duplicated computation
by saving the size in a var. No security concerns, just a small
optimization.

Signed-off-by: Denis Efremov <efremov@linux.com>
---
arch/x86/kvm/cpuid.c | 9 ++++-----
virt/kvm/kvm_main.c | 8 ++++----
2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 901cd1fdecd9..3363b7531af1 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -184,14 +184,13 @@ int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
goto out;
r = -ENOMEM;
if (cpuid->nent) {
- cpuid_entries =
- vmalloc(array_size(sizeof(struct kvm_cpuid_entry),
- cpuid->nent));
+ const size_t size = array_size(sizeof(struct kvm_cpuid_entry),
+ cpuid->nent);
+ cpuid_entries = vmalloc(size);
if (!cpuid_entries)
goto out;
r = -EFAULT;
- if (copy_from_user(cpuid_entries, entries,
- cpuid->nent * sizeof(struct kvm_cpuid_entry)))
+ if (copy_from_user(cpuid_entries, entries, size))
goto out;
}
for (i = 0; i < cpuid->nent; i++) {
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 731c1e517716..001e1929e01c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3722,15 +3722,15 @@ static long kvm_vm_ioctl(struct file *filp,
if (routing.flags)
goto out;
if (routing.nr) {
+ const size_t size = array_size(sizeof(*entries),
+ routing.nr);
r = -ENOMEM;
- entries = vmalloc(array_size(sizeof(*entries),
- routing.nr));
+ entries = vmalloc(size);
if (!entries)
goto out;
r = -EFAULT;
urouting = argp;
- if (copy_from_user(entries, urouting->entries,
- routing.nr * sizeof(*entries)))
+ if (copy_from_user(entries, urouting->entries, size))
goto out_free_irq_routing;
}
r = kvm_set_irq_routing(kvm, entries, routing.nr,
--
2.26.2
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