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[xen master] xen/dmop: Strip __XEN_TOOLS__ header guard from public ABI

commit 368096b9c4a273be58dd897e996e3e010bcfc21b
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Thu Mar 4 22:30:00 2021 +0000
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Thu Mar 11 17:27:48 2021 +0000

    xen/dmop: Strip __XEN_TOOLS__ header guard from public ABI
    __XEN_TOOLS__ is really there to separate the unstable from stable 
    Exactly as with c/s f40e1c52e4, stable interfaces shouldn't contain this
    That change actually broke the build with:
      include/xendevicemodel.h:52:5: error: unknown type name 'ioservid_t'
           ioservid_t *id);
    as libxendevicemodel.h now uses a type it can't see a typedef for.  However,
    nothing noticed because the header.chk logic is also broken (fixed
    Strip the guard from the public header, and remove compensation from
    devicemodel's private.h.  Fix the dmop design doc to discuss both reasons
    behind the the ABI design.
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
    Release-Acked-by: Ian Jackson <iwj@xxxxxxxxxxxxxx>
 docs/designs/dmop.pandoc         | 12 +++++++++---
 tools/libs/devicemodel/private.h |  2 --
 xen/include/public/hvm/dm_op.h   |  5 -----
 3 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/docs/designs/dmop.pandoc b/docs/designs/dmop.pandoc
index 8e9f95af47..49e52b1bcc 100644
--- a/docs/designs/dmop.pandoc
+++ b/docs/designs/dmop.pandoc
@@ -4,9 +4,15 @@ DMOP
-The aim of DMOP is to prevent a compromised device model from compromising
-domains other than the one it is providing emulation for (which is therefore
-likely already compromised).
+The DMOP hypercall has a new ABI design to solve problems in the Xen
+ecosystem.  First, the ABI is fully stable, to reduce the coupling between
+device models and the version of Xen.  Specifically, device model software
+using DMOP (be it user, stub domain or kernel software) need not be recompiled
+to match the version of the running hypervisor.
+Secondly, for device models in userspace, the ABI is designed specifically to
+allow a kernel to audit the memory ranges used, without having to know the
+internal structure of sub-ops.
 The problem occurs when you a device model issues an hypercall that
 includes references to user memory other than the operation structure
diff --git a/tools/libs/devicemodel/private.h b/tools/libs/devicemodel/private.h
index c4a225f8af..c24f3396bb 100644
--- a/tools/libs/devicemodel/private.h
+++ b/tools/libs/devicemodel/private.h
@@ -1,8 +1,6 @@
-#define __XEN_TOOLS__ 1
 #include <xentoollog.h>
 #include <xendevicemodel.h>
 #include <xencall.h>
diff --git a/xen/include/public/hvm/dm_op.h b/xen/include/public/hvm/dm_op.h
index ef7fbc0d3d..fa3f083fed 100644
--- a/xen/include/public/hvm/dm_op.h
+++ b/xen/include/public/hvm/dm_op.h
@@ -25,9 +25,6 @@
 #define __XEN_PUBLIC_HVM_DM_OP_H__
 #include "../xen.h"
-#if defined(__XEN__) || defined(__XEN_TOOLS__)
 #include "../event_channel.h"
 #ifndef uint64_aligned_t
@@ -491,8 +488,6 @@ struct xen_dm_op {
     } u;
-#endif /* __XEN__ || __XEN_TOOLS__ */
 struct xen_dm_op_buf {
     XEN_GUEST_HANDLE(void) h;
     xen_ulong_t size;
generated by git-patchbot for /home/xen/git/xen.git#master



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