lkml.org 
[lkml]   [2020]   [Dec]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH RFC 03/39] KVM: x86/xen: register shared_info page
From
Date
On Wed, 2019-02-20 at 20:15 +0000, Joao Martins wrote:
> +static int kvm_xen_shared_info_init(struct kvm *kvm, gfn_t gfn)
> +{
> + struct shared_info *shared_info;
> + struct page *page;
> +
> + page = gfn_to_page(kvm, gfn);
> + if (is_error_page(page))
> + return -EINVAL;
> +
> + kvm->arch.xen.shinfo_addr = gfn;
> +
> + shared_info = page_to_virt(page);
> + memset(shared_info, 0, sizeof(struct shared_info));
> + kvm->arch.xen.shinfo = shared_info;
> + return 0;
> +}
> +

Hm.

How come we get to pin the page and directly dereference it every time,
while kvm_setup_pvclock_page() has to use kvm_write_guest_cached()
instead?

If that was allowed, wouldn't it have been a much simpler fix for
CVE-2019-3016? What am I missing?

Should I rework these to use kvm_write_guest_cached()?


[unhandled content-type:application/x-pkcs7-signature]
\
 
 \ /
  Last update: 2020-12-01 14:09    [W:0.429 / U:22.272 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site