On Wed, Feb 17, 2021 at 09:21:36AM +0100, Jan Beulich wrote:
> Using copy_{from,to}_user(), this code was assuming to be called only by
> PV guests. Use copy_{from,to}_guest() instead, transforming the incoming
> structure field into a guest handle (the field should really have been
> one in the first place). Also do not transform the debuggee address into
> a pointer.
>
> Signed-off-by: Jan Beulich <jbeul...@suse.com>
Acked-by: Roger Pau Monné <roger....@citrix.com>
One minor comment below that can be taken care of when committing I
think.
> ---
> v2: Re-base (bug fix side effect was taken care of already).
>
> --- a/xen/arch/x86/debug.c
> +++ b/xen/arch/x86/debug.c
> @@ -108,12 +108,11 @@ dbg_pv_va2mfn(dbgva_t vaddr, struct doma
> }
>
> /* Returns: number of bytes remaining to be copied */
> -static unsigned int dbg_rw_guest_mem(struct domain *dp, void * __user gaddr,
> - void * __user buf, unsigned int len,
> - bool toaddr, uint64_t pgd3)
> +static unsigned int dbg_rw_guest_mem(struct domain *dp, unsigned long addr,
> + XEN_GUEST_HANDLE_PARAM(void) buf,
> + unsigned int len, bool toaddr,
> + uint64_t pgd3)
> {
> - unsigned long addr = (unsigned long)gaddr;
> -
> while ( len > 0 )
> {
> char *va;
> @@ -134,20 +133,18 @@ static unsigned int dbg_rw_guest_mem(str
>
> if ( toaddr )
> {
> - copy_from_user(va, buf, pagecnt); /* va = buf */
> + copy_from_guest(va, buf, pagecnt);
> paging_mark_dirty(dp, mfn);
> }
> else
> - {
> - copy_to_user(buf, va, pagecnt); /* buf = va */
> - }
> + copy_to_guest(buf, va, pagecnt);
>
> unmap_domain_page(va);
> if ( !gfn_eq(gfn, INVALID_GFN) )
> put_gfn(dp, gfn_x(gfn));
>
> addr += pagecnt;
> - buf += pagecnt;
> + guest_handle_add_offset(buf, pagecnt);
> len -= pagecnt;
> }
>
> @@ -161,7 +158,7 @@ static unsigned int dbg_rw_guest_mem(str
> * pgd3: value of init_mm.pgd[3] in guest. see above.
> * Returns: number of bytes remaining to be copied.
> */
> -unsigned int dbg_rw_mem(void * __user addr, void * __user buf,
> +unsigned int dbg_rw_mem(unsigned long gva, XEN_GUEST_HANDLE_PARAM(void) buf,
> unsigned int len, domid_t domid, bool toaddr,
> uint64_t pgd3)
You change the prototype below to make pgd3 unsigned long, so you
should change the type here also? (and likely in dbg_rw_guest_mem?)
Thanks, Roger.
