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authorVitaly Kuznetsov <vkuznets@redhat.com>2020-10-01 16:05:40 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2020-10-22 00:36:33 +0300
commit255cbecfe0c9466ade041fe381dde18a61cca549 (patch)
treeeb014077d77a9a114b3de6f3a12a9da20cd705f8 /arch/x86/kvm/cpuid.c
parentf69858fcc727f8098419f3c595678e671bd2d8b7 (diff)
downloadlinux-255cbecfe0c9466ade041fe381dde18a61cca549.tar.xz
KVM: x86: allocate vcpu->arch.cpuid_entries dynamically
The current limit for guest CPUID leaves (KVM_MAX_CPUID_ENTRIES, 80) is reported to be insufficient but before we bump it let's switch to allocating vcpu->arch.cpuid_entries[] array dynamically. Currently, 'struct kvm_cpuid_entry2' is 40 bytes so vcpu->arch.cpuid_entries is 3200 bytes which accounts for 1/4 of the whole 'struct kvm_vcpu_arch' but having it pre-allocated (for all vCPUs which we also pre-allocate) gives us no real benefits. Another plus of the dynamic allocation is that we now do kvm_check_cpuid() check before we assign anything to vcpu->arch.cpuid_nent/cpuid_entries so no changes are made in case the check fails. Opportunistically remove unneeded 'out' labels from kvm_vcpu_ioctl_set_cpuid()/kvm_vcpu_ioctl_set_cpuid2() and return directly whenever possible. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20201001130541.1398392-3-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Diffstat (limited to 'arch/x86/kvm/cpuid.c')
-rw-r--r--arch/x86/kvm/cpuid.c89
1 files changed, 51 insertions, 38 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 2e4228ccbe2a..5a62fa4ee493 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -217,46 +217,53 @@ int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
struct kvm_cpuid_entry __user *entries)
{
int r, i;
- struct kvm_cpuid_entry *cpuid_entries = NULL;
+ struct kvm_cpuid_entry *e = NULL;
+ struct kvm_cpuid_entry2 *e2 = NULL;
- r = -E2BIG;
if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
- goto out;
+ return -E2BIG;
+
if (cpuid->nent) {
- cpuid_entries = vmemdup_user(entries,
- array_size(sizeof(struct kvm_cpuid_entry),
- cpuid->nent));
- if (IS_ERR(cpuid_entries)) {
- r = PTR_ERR(cpuid_entries);
- goto out;
+ e = vmemdup_user(entries, array_size(sizeof(*e), cpuid->nent));
+ if (IS_ERR(e))
+ return PTR_ERR(e);
+
+ e2 = kvmalloc_array(cpuid->nent, sizeof(*e2), GFP_KERNEL_ACCOUNT);
+ if (!e2) {
+ r = -ENOMEM;
+ goto out_free_cpuid;
}
}
for (i = 0; i < cpuid->nent; i++) {
- vcpu->arch.cpuid_entries[i].function = cpuid_entries[i].function;
- vcpu->arch.cpuid_entries[i].eax = cpuid_entries[i].eax;
- vcpu->arch.cpuid_entries[i].ebx = cpuid_entries[i].ebx;
- vcpu->arch.cpuid_entries[i].ecx = cpuid_entries[i].ecx;
- vcpu->arch.cpuid_entries[i].edx = cpuid_entries[i].edx;
- vcpu->arch.cpuid_entries[i].index = 0;
- vcpu->arch.cpuid_entries[i].flags = 0;
- vcpu->arch.cpuid_entries[i].padding[0] = 0;
- vcpu->arch.cpuid_entries[i].padding[1] = 0;
- vcpu->arch.cpuid_entries[i].padding[2] = 0;
+ e2[i].function = e[i].function;
+ e2[i].eax = e[i].eax;
+ e2[i].ebx = e[i].ebx;
+ e2[i].ecx = e[i].ecx;
+ e2[i].edx = e[i].edx;
+ e2[i].index = 0;
+ e2[i].flags = 0;
+ e2[i].padding[0] = 0;
+ e2[i].padding[1] = 0;
+ e2[i].padding[2] = 0;
}
- vcpu->arch.cpuid_nent = cpuid->nent;
- r = kvm_check_cpuid(vcpu->arch.cpuid_entries, cpuid->nent);
+
+ r = kvm_check_cpuid(e2, cpuid->nent);
if (r) {
- vcpu->arch.cpuid_nent = 0;
- kvfree(cpuid_entries);
- goto out;
+ kvfree(e2);
+ goto out_free_cpuid;
}
+ kvfree(vcpu->arch.cpuid_entries);
+ vcpu->arch.cpuid_entries = e2;
+ vcpu->arch.cpuid_nent = cpuid->nent;
+
cpuid_fix_nx_cap(vcpu);
kvm_update_cpuid_runtime(vcpu);
kvm_vcpu_after_set_cpuid(vcpu);
- kvfree(cpuid_entries);
-out:
+out_free_cpuid:
+ kvfree(e);
+
return r;
}
@@ -264,26 +271,32 @@ int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
struct kvm_cpuid2 *cpuid,
struct kvm_cpuid_entry2 __user *entries)
{
+ struct kvm_cpuid_entry2 *e2 = NULL;
int r;
- r = -E2BIG;
if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
- goto out;
- r = -EFAULT;
- if (copy_from_user(&vcpu->arch.cpuid_entries, entries,
- cpuid->nent * sizeof(struct kvm_cpuid_entry2)))
- goto out;
- vcpu->arch.cpuid_nent = cpuid->nent;
- r = kvm_check_cpuid(vcpu->arch.cpuid_entries, cpuid->nent);
+ return -E2BIG;
+
+ if (cpuid->nent) {
+ e2 = vmemdup_user(entries, array_size(sizeof(*e2), cpuid->nent));
+ if (IS_ERR(e2))
+ return PTR_ERR(e2);
+ }
+
+ r = kvm_check_cpuid(e2, cpuid->nent);
if (r) {
- vcpu->arch.cpuid_nent = 0;
- goto out;
+ kvfree(e2);
+ return r;
}
+ kvfree(vcpu->arch.cpuid_entries);
+ vcpu->arch.cpuid_entries = e2;
+ vcpu->arch.cpuid_nent = cpuid->nent;
+
kvm_update_cpuid_runtime(vcpu);
kvm_vcpu_after_set_cpuid(vcpu);
-out:
- return r;
+
+ return 0;
}
int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,