[src/trunk]: src/sys/arch/xen/xen parse indirect_op using appropriate 32/64-b...

[jdolecek <jdolecek%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/ac836768d4ba
branches:  trunk
changeset: 1009526:ac836768d4ba
user:      jdolecek <jdolecek%NetBSD.org@localhost>
date:      Sat Apr 25 20:05:25 2020 +0000

description:
parse indirect_op using appropriate 32/64-bit access types, this fixes
the BLKIF_OP_INDIRECT handling for 32-bit DomU running against 64-bit Dom0,
problem reported and fix tested by Manuel

make sure to use the provided indirect_op when reporting back errors

diffstat:

 sys/arch/xen/xen/xbdback_xenbus.c |  55 ++++++++++++++++++++++++--------------
 1 files changed, 34 insertions(+), 21 deletions(-)

diffs (134 lines):

diff -r af1e7194abdd -r ac836768d4ba sys/arch/xen/xen/xbdback_xenbus.c
--- a/sys/arch/xen/xen/xbdback_xenbus.c Sat Apr 25 18:56:26 2020 +0000
+++ b/sys/arch/xen/xen/xbdback_xenbus.c Sat Apr 25 20:05:25 2020 +0000
@@ -1,4 +1,4 @@
-/*      $NetBSD: xbdback_xenbus.c,v 1.91 2020/04/25 15:26:18 bouyer Exp $      */
+/*      $NetBSD: xbdback_xenbus.c,v 1.92 2020/04/25 20:05:25 jdolecek Exp $      */
 
 /*
  * Copyright (c) 2006 Manuel Bouyer.
@@ -26,7 +26,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xbdback_xenbus.c,v 1.91 2020/04/25 15:26:18 bouyer Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xbdback_xenbus.c,v 1.92 2020/04/25 20:05:25 jdolecek Exp $");
 
 #include <sys/buf.h>
 #include <sys/condvar.h>
@@ -966,9 +966,13 @@
        blkif_request_t *req, *reqn;
        blkif_x86_32_request_t *req32;
        blkif_x86_64_request_t *req64;
-       blkif_request_indirect_t *rin;
+       blkif_request_indirect_t *rinn;
+       blkif_x86_32_request_indirect_t *rin32;
+       blkif_x86_64_request_indirect_t *rin64;
 
        if (xbdi->xbdi_ring.ring_n.req_cons != xbdi->xbdi_req_prod) {
+               uint8_t real_op = 0xff;
+
                req = &xbdi->xbdi_xen_req;
                memset(req, 0, sizeof(*req));
 
@@ -976,19 +980,31 @@
                case XBDIP_NATIVE:
                        reqn = RING_GET_REQUEST(&xbdi->xbdi_ring.ring_n,
                            xbdi->xbdi_ring.ring_n.req_cons);
-                       req->operation = reqn->operation;
+                       real_op = req->operation = reqn->operation;
+                       if (real_op == BLKIF_OP_INDIRECT) {
+                               rinn = (blkif_request_indirect_t *)reqn;
+                               real_op = rinn->indirect_op;
+                       }
                        req->id = reqn->id;
                        break;
                case XBDIP_32:
                        req32 = RING_GET_REQUEST(&xbdi->xbdi_ring.ring_32,
                            xbdi->xbdi_ring.ring_n.req_cons);
-                       req->operation = req32->operation;
+                       real_op = req->operation = req32->operation;
+                       if (real_op == BLKIF_OP_INDIRECT) {
+                               rin32 = (blkif_x86_32_request_indirect_t*)req32;
+                               real_op = rin32->indirect_op;
+                       }
                        req->id = req32->id;
                        break;
                case XBDIP_64:
                        req64 = RING_GET_REQUEST(&xbdi->xbdi_ring.ring_64,
                            xbdi->xbdi_ring.ring_n.req_cons);
-                       req->operation = req64->operation;
+                       real_op = req->operation = req64->operation;
+                       if (real_op == BLKIF_OP_INDIRECT) {
+                               rin64 = (blkif_x86_64_request_indirect_t*)req64;
+                               real_op = rin64->indirect_op;
+                       }
                        req->id = req64->id;
                        break;
                }
@@ -1002,16 +1018,13 @@
                switch (req->operation) {
                case BLKIF_OP_INDIRECT:
                        /* just check indirect_op, rest is handled later */
-                       rin = (blkif_request_indirect_t *)
-                           RING_GET_REQUEST(&xbdi->xbdi_ring.ring_n,
-                               xbdi->xbdi_ring.ring_n.req_cons);
-                       if (rin->indirect_op != BLKIF_OP_READ &&
-                           rin->indirect_op != BLKIF_OP_WRITE) {
+                       if (real_op != BLKIF_OP_READ &&
+                           real_op != BLKIF_OP_WRITE) {
                                if (ratecheck(&xbdi->xbdi_lasterr_time,
                                    &xbdback_err_intvl)) {
                                        printf("%s: unknown ind operation %d\n",
                                            xbdi->xbdi_name,
-                                           rin->indirect_op);
+                                           real_op);
                                }
                                goto fail;
                        }
@@ -1031,7 +1044,7 @@
                                    xbdi->xbdi_name, req->operation);
                        }
 fail:
-                       xbdback_send_reply(xbdi, req->id, req->operation,
+                       xbdback_send_reply(xbdi, req->id, real_op,
                            BLKIF_RSP_ERROR);
                        xbdi->xbdi_cont = xbdback_co_main_incr;
                        break;
@@ -1136,12 +1149,6 @@
        KASSERT(req->operation == BLKIF_OP_READ ||
            req->operation == BLKIF_OP_WRITE ||
            req->operation == BLKIF_OP_INDIRECT);
-       if (req->operation == BLKIF_OP_WRITE) {
-               if (xbdi->xbdi_ro) {
-                       error = EROFS;
-                       goto end;
-               }
-       }
 
        /* copy request segments */
        switch (xbdi->xbdi_proto) {
@@ -1212,6 +1219,13 @@
                break;
        }
 
+       if (req->operation == BLKIF_OP_WRITE) {
+               if (xbdi->xbdi_ro) {
+                       error = EROFS;
+                       goto end;
+               }
+       }
+
        /* Max value checked already earlier */
        if (req->nr_segments < 1)
                goto bad_nr_segments;
@@ -1228,8 +1242,7 @@
        /* FALLTHROUGH */
 
  end:
-       xbdback_send_reply(xbdi, xbdi->xbdi_xen_req.id,
-           xbdi->xbdi_xen_req.operation,
+       xbdback_send_reply(xbdi, req->id, req->operation,
            (error == EROFS) ? BLKIF_RSP_EOPNOTSUPP : BLKIF_RSP_ERROR);
        xbdi->xbdi_cont = xbdback_co_main_incr;
        return xbdi;