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Subject[PATCH 2/3] KVM: x86: Make filter arg for set_msr_filter()
Date
In the next patch we want to introduce a second caller to
set_msr_filter() which constructs its own filter list on the stack.
Refactor the original function so it takes it as argument instead of
reading it through copy_from_user().

Signed-off-by: Alexander Graf <graf@amazon.com>
---
arch/x86/kvm/x86.c | 31 +++++++++++++++++--------------
1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b0c47b41c264..19f060ce577f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6399,26 +6399,22 @@ static int kvm_add_msr_filter(struct kvm_x86_msr_filter *msr_filter,
return 0;
}

-static int kvm_vm_ioctl_set_msr_filter(struct kvm *kvm, void __user *argp)
+static int kvm_vm_ioctl_set_msr_filter(struct kvm *kvm,
+ struct kvm_msr_filter *filter)
{
- struct kvm_msr_filter __user *user_msr_filter = argp;
struct kvm_x86_msr_filter *new_filter, *old_filter;
- struct kvm_msr_filter filter;
bool default_allow;
bool empty = true;
int r = 0;
u32 i;

- if (copy_from_user(&filter, user_msr_filter, sizeof(filter)))
- return -EFAULT;
-
- if (filter.flags & ~KVM_MSR_FILTER_DEFAULT_DENY)
+ if (filter->flags & ~KVM_MSR_FILTER_DEFAULT_DENY)
return -EINVAL;

- for (i = 0; i < ARRAY_SIZE(filter.ranges); i++)
- empty &= !filter.ranges[i].nmsrs;
+ for (i = 0; i < ARRAY_SIZE(filter->ranges); i++)
+ empty &= !filter->ranges[i].nmsrs;

- default_allow = !(filter.flags & KVM_MSR_FILTER_DEFAULT_DENY);
+ default_allow = !(filter->flags & KVM_MSR_FILTER_DEFAULT_DENY);
if (empty && !default_allow)
return -EINVAL;

@@ -6426,8 +6422,8 @@ static int kvm_vm_ioctl_set_msr_filter(struct kvm *kvm, void __user *argp)
if (!new_filter)
return -ENOMEM;

- for (i = 0; i < ARRAY_SIZE(filter.ranges); i++) {
- r = kvm_add_msr_filter(new_filter, &filter.ranges[i]);
+ for (i = 0; i < ARRAY_SIZE(filter->ranges); i++) {
+ r = kvm_add_msr_filter(new_filter, &filter->ranges[i]);
if (r) {
kvm_free_msr_filter(new_filter);
return r;
@@ -6872,9 +6868,16 @@ long kvm_arch_vm_ioctl(struct file *filp,
case KVM_SET_PMU_EVENT_FILTER:
r = kvm_vm_ioctl_set_pmu_event_filter(kvm, argp);
break;
- case KVM_X86_SET_MSR_FILTER:
- r = kvm_vm_ioctl_set_msr_filter(kvm, argp);
+ case KVM_X86_SET_MSR_FILTER: {
+ struct kvm_msr_filter __user *user_msr_filter = argp;
+ struct kvm_msr_filter filter;
+
+ if (copy_from_user(&filter, user_msr_filter, sizeof(filter)))
+ return -EFAULT;
+
+ r = kvm_vm_ioctl_set_msr_filter(kvm, &filter);
break;
+ }
default:
r = -ENOTTY;
}
--
2.37.1



Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879



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