| Message ID | 20210512164800.26236-1-jgross@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | include/public: add RING_RESPONSE_PROD_OVERFLOW macro | expand |
On 12.05.2021 18:48, Juergen Gross wrote: > Add a new RING_RESPONSE_PROD_OVERFLOW() macro for being able to > detect an ill-behaved backend tampering with the response producer > index. > > Signed-off-by: Juergen Gross <jgross@suse.com> Acked-by: Jan Beulich <jbeulich@suse.com> > --- a/xen/include/public/io/ring.h > +++ b/xen/include/public/io/ring.h > @@ -259,6 +259,10 @@ typedef struct __name##_back_ring __name##_back_ring_t > #define RING_REQUEST_PROD_OVERFLOW(_r, _prod) \ > (((_prod) - (_r)->rsp_prod_pvt) > RING_SIZE(_r)) > > +/* Ill-behaved backend determination: Can there be this many responses? */ > +#define RING_RESPONSE_PROD_OVERFLOW(_r, _prod) \ > + (((_prod) - (_r)->rsp_cons) > RING_SIZE(_r)) > + > #define RING_PUSH_REQUESTS(_r) do { \ > xen_wmb(); /* back sees requests /before/ updated producer index */ \ > (_r)->sring->req_prod = (_r)->req_prod_pvt; \ >
diff --git a/xen/include/public/io/ring.h b/xen/include/public/io/ring.h index 0b08b2697e..c486c457e0 100644 --- a/xen/include/public/io/ring.h +++ b/xen/include/public/io/ring.h @@ -259,6 +259,10 @@ typedef struct __name##_back_ring __name##_back_ring_t #define RING_REQUEST_PROD_OVERFLOW(_r, _prod) \ (((_prod) - (_r)->rsp_prod_pvt) > RING_SIZE(_r)) +/* Ill-behaved backend determination: Can there be this many responses? */ +#define RING_RESPONSE_PROD_OVERFLOW(_r, _prod) \ + (((_prod) - (_r)->rsp_cons) > RING_SIZE(_r)) + #define RING_PUSH_REQUESTS(_r) do { \ xen_wmb(); /* back sees requests /before/ updated producer index */ \ (_r)->sring->req_prod = (_r)->req_prod_pvt; \
Add a new RING_RESPONSE_PROD_OVERFLOW() macro for being able to detect an ill-behaved backend tampering with the response producer index. Signed-off-by: Juergen Gross <jgross@suse.com> --- xen/include/public/io/ring.h | 4 ++++ 1 file changed, 4 insertions(+)