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KVM: Write the per-page "segment" when clearing (part of) a guest page

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Pass "seg" instead of "len" when writing guest memory in kvm_clear_guest(),
as "seg" holds the number of bytes to write for the current page, while
"len" holds the total bytes remaining.

Luckily, all users of kvm_clear_guest() are guaranteed to not cross a page
boundary, and so the bug is unhittable in the current code base.

Fixes: 2f5414423e ("KVM: remove kvm_clear_guest_page")
Reported-by: zyr_ms@outlook.com
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219104
Link: https://lore.kernel.org/r/20240829191413.900740-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson 2024-08-29 12:14:12 -07:00
parent e027ba1b83
commit ec495f2ab1
1 changed files with 1 additions and 1 deletions
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2
virt/kvm/kvm_main.c
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@ -3581,7 +3581,7 @@ int kvm_clear_guest(struct kvm *kvm, gpa_t gpa, unsigned long len)
int ret;
while ((seg = next_segment(len, offset)) != 0) {
ret = kvm_write_guest_page(kvm, gfn, zero_page, offset, len);
ret = kvm_write_guest_page(kvm, gfn, zero_page, offset, seg);
if (ret < 0)
return ret;
offset = 0;