[Qemu-devel] [PATCH v8 00/16] xen: xen-domid-restrict improvements

[Qemu-devel] [PATCH v8 00/16] xen: xen-domid-restrict improvements

[Ian Jackson]

This series provides necessary support for running qemu as a Xen
device model without power equivalent to root.  In particular, it
makes -xen-domid-restrict effective.

Compared to v8, it addresses review comments.

      01/16 checkpatch: Add xendevicemodel_handle to the list of
  r   02/16 AccelClass: Introduce accel_setup_post
 * a  03/16 xen: link against xentoolcore
   a  04/16 xen: restrict: use xentoolcore_restrict_all
 * a  05/16 xen: defer call to xen_restrict until just before
   a  06/16 xen: destroy_hvm_domain: Move reason into a variable
   a  07/16 xen: move xc_interface compatibility fallback further
  r   08/16 xen: destroy_hvm_domain: Try xendevicemodel_shutdown
      09/16 os-posix: cleanup: Replace fprintfs with error_report in change_...
  r   10/16 os-posix: Provide new -runas <uid>:<gid> facility
   a  11/16 xen: Use newly added dmops for mapping VGA memory
   a  12/16 xen: Remove now-obsolete xen_xc_domain_add_to_physmap
   a  13/16 xen: Expect xenstore write to fail when restricted
 *r   14/16 os-posix: cleanup: Replace fprintf with error_report in remaining
  r   15/16 os-posix: cleanup: Replace perror with error_report
 *    16/16 configure: do_compiler: Dump some extra info under bash

 r = reviewed (by someone other than me)
 a = acked
 * = amended patch

Thanks for your attention.

Ian.

[Qemu-devel] [PATCH 01/16] checkpatch: Add xendevicemodel_handle to the list of types

[Ian Jackson]

This avoids checkpatch misparsing (as statements) long function
definitions or declarations, which sometimes start with constructs
like this:

  static inline int xendevicemodel_relocate_memory(
      xendevicemodel_handle *dmod, domid_t domid, ...

The type xendevicemodel_handle does not conform to Qemu CODING_STYLE,
which would suggest CamelCase.  However, it is a type defined by the
Xen Project in xen.git.  It would be possible to introduce a typedef
to allow the qemu code to refer to it by a differently-spelled name,
but that would obfuscate more than it would clarify.

CC: Eric Blake <eblake@redhat.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
---
v7: Added comment to commit message about why we are not renaming
    this type to CamelCase.
v6.1: New patch
---
 scripts/checkpatch.pl | 1 +
 1 file changed, 1 insertion(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index d52207a..5b8735d 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -266,6 +266,7 @@ our @typeList = (
 	qr{target_(?:u)?long},
 	qr{hwaddr},
 	qr{xml${Ident}},
+	qr{xendevicemodel_handle},
 );
 
 # This can be modified by sub possible.  Since it can be empty, be careful
-- 
2.1.4

Re: [Qemu-devel] [PATCH 01/16] checkpatch: Add xendevicemodel_handle to the list of types

[Ian Jackson]

(expanding the CC to include everyone that get_maintainer suggests)

Ian Jackson writes ("[PATCH 01/16] checkpatch: Add xendevicemodel_handle to the list of types"):
> This avoids checkpatch misparsing (as statements) long function
> definitions or declarations, which sometimes start with constructs
> like this:
> 
>   static inline int xendevicemodel_relocate_memory(
>       xendevicemodel_handle *dmod, domid_t domid, ...
> 
> The type xendevicemodel_handle does not conform to Qemu CODING_STYLE,
> which would suggest CamelCase.  However, it is a type defined by the
> Xen Project in xen.git.  It would be possible to introduce a typedef
> to allow the qemu code to refer to it by a differently-spelled name,
> but that would obfuscate more than it would clarify.

This patch has been posted in substantially similar form quite a few
times now.  Paolo Bonzini understandably suggested that renaming the
variable would be better but that's not within qemu's bailiwick as I
say above.

I think everything else in this series has a review and/or an ack.
So I would like to send a pull request.

Does someone want to review this patch ?  Should I drop it and just
let checkpatch complain ?  Shold I include it in my pull request
anyway ?

Thanks,
Ian.

Re: [Qemu-devel] [PATCH 01/16] checkpatch: Add xendevicemodel_handle to the list of types

[Eric Blake]

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On 04/26/2018 06:06 AM, Ian Jackson wrote:
> (expanding the CC to include everyone that get_maintainer suggests)
> 
> Ian Jackson writes ("[PATCH 01/16] checkpatch: Add xendevicemodel_handle to the list of types"):
>> This avoids checkpatch misparsing (as statements) long function
>> definitions or declarations, which sometimes start with constructs
>> like this:
>>
>>   static inline int xendevicemodel_relocate_memory(
>>       xendevicemodel_handle *dmod, domid_t domid, ...
>>
>> The type xendevicemodel_handle does not conform to Qemu CODING_STYLE,
>> which would suggest CamelCase.  However, it is a type defined by the
>> Xen Project in xen.git.  It would be possible to introduce a typedef
>> to allow the qemu code to refer to it by a differently-spelled name,
>> but that would obfuscate more than it would clarify.
> 
> This patch has been posted in substantially similar form quite a few
> times now.  Paolo Bonzini understandably suggested that renaming the
> variable would be better but that's not within qemu's bailiwick as I
> say above.
> 
> I think everything else in this series has a review and/or an ack.
> So I would like to send a pull request.
> 
> Does someone want to review this patch ?  Should I drop it and just
> let checkpatch complain ?  Shold I include it in my pull request
> anyway ?

If no one has commented on what seems pretty trivial (especially since
checkpatch.pl has no official maintainer, but is more of a
"whoever-touched-it-last" file at the moment), then including the patch
in your pull request is perfectly acceptable.  As a maintainer, it is
also perfectly acceptable for you to ignore false positives from
checkpatch (although documenting it in the commit message and/or cover
letter never hurts, when you are intentionally ignoring a false positive).

But, as there has also been a recent patch to teach checkpatch about
glib types [1], your patch makes sense (any merge conflict between your
patch and that one will be obvious to resolve).  So on that grounds,

Reviewed-by: Eric Blake <eblake@redhat.com>

[1] https://lists.gnu.org/archive/html/qemu-devel/2018-04/msg04179.html

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


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Re: [Qemu-devel] [PATCH 01/16] checkpatch: Add xendevicemodel_handle to the list of types

[Ian Jackson]

> If no one has commented on what seems pretty trivial (especially since
> checkpatch.pl has no official maintainer, but is more of a
> "whoever-touched-it-last" file at the moment), then including the patch
> in your pull request is perfectly acceptable.  As a maintainer, it is
> also perfectly acceptable for you to ignore false positives from
> checkpatch (although documenting it in the commit message and/or cover
> letter never hurts, when you are intentionally ignoring a false positive).

Thanks for the comprehensive response.

> But, as there has also been a recent patch to teach checkpatch about
> glib types [1], your patch makes sense (any merge conflict between your
> patch and that one will be obvious to resolve).  So on that grounds,
> 
> Reviewed-by: Eric Blake <eblake@redhat.com>

Thanks.

I will rebase onto current master before sending a pull request, so
I'll get to resolve that conflict.

Regards,
Ian.

[Qemu-devel] [PATCH 02/16] AccelClass: Introduce accel_setup_post

[Ian Jackson]

This is called just before os_setup_post.  Currently none of the
accelerators provide this hook, but the Xen one is going to provide
one in a moment.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
---
v7: New patch in this version of the series
---
 accel/accel.c          | 9 +++++++++
 include/sysemu/accel.h | 3 +++
 vl.c                   | 1 +
 3 files changed, 13 insertions(+)

diff --git a/accel/accel.c b/accel/accel.c
index 93e2434..9cfab11 100644
--- a/accel/accel.c
+++ b/accel/accel.c
@@ -126,6 +126,15 @@ void accel_register_compat_props(AccelState *accel)
     register_compat_props_array(class->global_props);
 }
 
+void accel_setup_post(MachineState *ms)
+{
+    AccelState *accel = ms->accelerator;
+    AccelClass *acc = ACCEL_GET_CLASS(accel);
+    if (acc->setup_post) {
+        acc->setup_post(ms, accel);
+    }
+}
+
 static void register_accel_types(void)
 {
     type_register_static(&accel_type);
diff --git a/include/sysemu/accel.h b/include/sysemu/accel.h
index 5a632ce..637358f 100644
--- a/include/sysemu/accel.h
+++ b/include/sysemu/accel.h
@@ -40,6 +40,7 @@ typedef struct AccelClass {
     const char *name;
     int (*available)(void);
     int (*init_machine)(MachineState *ms);
+    void (*setup_post)(MachineState *ms, AccelState *accel);
     bool *allowed;
     /*
      * Array of global properties that would be applied when specific
@@ -68,5 +69,7 @@ extern unsigned long tcg_tb_size;
 void configure_accelerator(MachineState *ms);
 /* Register accelerator specific global properties */
 void accel_register_compat_props(AccelState *accel);
+/* Called just before os_setup_post (ie just before drop OS privs) */
+void accel_setup_post(MachineState *ms);
 
 #endif
diff --git a/vl.c b/vl.c
index fce1fd1..36c5bd4 100644
--- a/vl.c
+++ b/vl.c
@@ -4729,6 +4729,7 @@ int main(int argc, char **argv, char **envp)
         vm_start();
     }
 
+    accel_setup_post(current_machine);
     os_setup_post();
 
     main_loop();
-- 
2.1.4

[Qemu-devel] [PATCH 03/16] xen: link against xentoolcore

[Ian Jackson]

From: Anthony PERARD <anthony.perard@citrix.com>

Xen libraries in 4.10 include a new xentoolcore library.  This
contains the xentoolcore_restrict_all function which we are about to
want to use.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
---
v8: In pkg-config branch, add xentoolcore conditionally.
    This cope with Xen 4.9 found via pkg-config.
v5: More truthful commit message.
---
 configure | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/configure b/configure
index 0a19b03..5cf9dde 100755
--- a/configure
+++ b/configure
@@ -2189,6 +2189,9 @@ if test "$xen" != "no" ; then
     xen=yes
     xen_pc="xencontrol xenstore xenguest xenforeignmemory xengnttab"
     xen_pc="$xen_pc xenevtchn xendevicemodel"
+    if $pkg_config --exists xentoolcore; then
+      xen_pc="$xen_pc xentoolcore"
+    fi
     QEMU_CFLAGS="$QEMU_CFLAGS $($pkg_config --cflags $xen_pc)"
     libs_softmmu="$($pkg_config --libs $xen_pc) $libs_softmmu"
     LDFLAGS="$($pkg_config --libs $xen_pc) $LDFLAGS"
@@ -2220,18 +2223,20 @@ EOF
         cat > $TMPC <<EOF &&
 #undef XC_WANT_COMPAT_MAP_FOREIGN_API
 #include <xenforeignmemory.h>
+#include <xentoolcore.h>
 int main(void) {
   xenforeignmemory_handle *xfmem;
 
   xfmem = xenforeignmemory_open(0, 0);
   xenforeignmemory_map2(xfmem, 0, 0, 0, 0, 0, 0, 0);
+  xentoolcore_restrict_all(0);
 
   return 0;
 }
 EOF
-        compile_prog "" "$xen_libs -lxendevicemodel $xen_stable_libs"
+        compile_prog "" "$xen_libs -lxendevicemodel $xen_stable_libs -lxentoolcore"
       then
-      xen_stable_libs="-lxendevicemodel $xen_stable_libs"
+      xen_stable_libs="-lxendevicemodel $xen_stable_libs -lxentoolcore"
       xen_ctrl_version=41000
       xen=yes
     elif
-- 
2.1.4

[Qemu-devel] [PATCH 04/16] xen: restrict: use xentoolcore_restrict_all

[Ian Jackson]

And insist that it works.

Drop individual use of xendevicemodel_restrict and
xenforeignmemory_restrict.  These are not actually effective in this
version of qemu, because qemu has a large number of fds open onto
various Xen control devices.

The restriction arrangements are still not right, because the
restriction needs to be done very late - after qemu has opened all of
its control fds.

xentoolcore_restrict_all and xentoolcore.h are available in Xen 4.10
and later, only.  Provide a compatibility stub.  And drop the
compatibility stubs for the old functions.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
---
v2: Modify the compatibility code, too.
    Bump this patch ahead of "defer call to xen_restrict until running"
    Retain call to xentoolcore_restrict_all
---
 include/hw/xen/xen_common.h | 46 +++++++++++----------------------------------
 1 file changed, 11 insertions(+), 35 deletions(-)

diff --git a/include/hw/xen/xen_common.h b/include/hw/xen/xen_common.h
index 64a978e..1766bb9 100644
--- a/include/hw/xen/xen_common.h
+++ b/include/hw/xen/xen_common.h
@@ -91,6 +91,16 @@ static inline void *xenforeignmemory_map2(xenforeignmemory_handle *h,
     return xenforeignmemory_map(h, dom, prot, pages, arr, err);
 }
 
+static inline int xentoolcore_restrict_all(domid_t domid)
+{
+    errno = ENOTTY;
+    return -1;
+}
+
+#else /* CONFIG_XEN_CTRL_INTERFACE_VERSION >= 41000 */
+
+#include <xentoolcore.h>
+
 #endif
 
 #if CONFIG_XEN_CTRL_INTERFACE_VERSION < 40900
@@ -218,20 +228,6 @@ static inline int xendevicemodel_set_mem_type(
     return xc_hvm_set_mem_type(dmod, domid, mem_type, first_pfn, nr);
 }
 
-static inline int xendevicemodel_restrict(
-    xendevicemodel_handle *dmod, domid_t domid)
-{
-    errno = ENOTTY;
-    return -1;
-}
-
-static inline int xenforeignmemory_restrict(
-    xenforeignmemory_handle *fmem, domid_t domid)
-{
-    errno = ENOTTY;
-    return -1;
-}
-
 #else /* CONFIG_XEN_CTRL_INTERFACE_VERSION >= 40900 */
 
 #undef XC_WANT_COMPAT_DEVICEMODEL_API
@@ -290,28 +286,8 @@ static inline int xen_modified_memory(domid_t domid, uint64_t first_pfn,
 static inline int xen_restrict(domid_t domid)
 {
     int rc;
-
-    /* Attempt to restrict devicemodel operations */
-    rc = xendevicemodel_restrict(xen_dmod, domid);
+    rc = xentoolcore_restrict_all(domid);
     trace_xen_domid_restrict(rc ? errno : 0);
-
-    if (rc < 0) {
-        /*
-         * If errno is ENOTTY then restriction is not implemented so
-         * there's no point in trying to restrict other types of
-         * operation, but it should not be treated as a failure.
-         */
-        if (errno == ENOTTY) {
-            return 0;
-        }
-
-        return rc;
-    }
-
-    /* Restrict foreignmemory operations */
-    rc = xenforeignmemory_restrict(xen_fmem, domid);
-    trace_xen_domid_restrict(rc ? errno : 0);
-
     return rc;
 }
 
-- 
2.1.4

[Qemu-devel] [PATCH 05/16] xen: defer call to xen_restrict until just before os_setup_post

[Ian Jackson]

We need to restrict *all* the control fds that qemu opens.  Looking in
/proc/PID/fd shows there are many; their allocation seems scattered
throughout Xen support code in qemu.

We must postpone the restrict call until roughly the same time as qemu
changes its uid, chroots (if applicable), and so on.

There doesn't seem to be an appropriate hook already.  The RunState
change hook fires at different times depending on exactly what mode
qemu is operating in.

And it appears that no-one but the Xen code wants a hook at this phase
of execution.  So, introduce a bare call to a new function
xen_setup_post, just before os_setup_post.  Also provide the
appropriate stub for when Xen compilation is disabled.

We do the restriction before rather than after os_setup_post, because
xen_restrict may need to open /dev/null, and os_setup_post might have
called chroot.

Currently this does not work with migration, because when running as
the Xen device model qemu needs to signal to the toolstack that it is
ready.  It currently does this using xenstore, and for incoming
migration (but not for ordinary startup) that happens after
os_setup_post.

It is correct that this happens late: we want the incoming migration
stream to be processed by a restricted qemu.  The fix for this will be
to do the startup notification a different way, without using
xenstore.  (QMP is probably a reasonable choice.)

So for now this restriction feature cannot be used in conjunction with
migration.  (Note that this is not a regression in this patch, because
previously the -xen-restrict-domid call was, in fact, simply
ineffective!)  We will revisit this in the Xen 4.11 release cycle.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Paolo Bonzini <pbonzini@redhat.com> (maintainer:X86)
CC: Richard Henderson <rth@twiddle.net> (maintainer:X86)
CC: Eduardo Habkost <ehabkost@redhat.com> (maintainer:X86)
CC: Michael S. Tsirkin <mst@redhat.com> (supporter:PC)
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
---
v8: Drop now-redundant hunk patching stubs/xen-hvm.c
v7: Use new AccelClass setup_post hook, rather than ad-hoc call
    in vl.c.
v5: Discuss problems with migration startup notification
    in the commit message.
v3: Do xen_setup_post just before, not just after, os_setup_post,
    to improve interaction with chroot.  Thanks to Ross Lagerwall.
---
 hw/i386/xen/xen-hvm.c |  8 --------
 hw/xen/xen-common.c   | 14 ++++++++++++++
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/hw/i386/xen/xen-hvm.c b/hw/i386/xen/xen-hvm.c
index f24b7d4..9c3b6b3 100644
--- a/hw/i386/xen/xen-hvm.c
+++ b/hw/i386/xen/xen-hvm.c
@@ -1254,14 +1254,6 @@ void xen_hvm_init(PCMachineState *pcms, MemoryRegion **ram_memory)
         goto err;
     }
 
-    if (xen_domid_restrict) {
-        rc = xen_restrict(xen_domid);
-        if (rc < 0) {
-            error_report("failed to restrict: error %d", errno);
-            goto err;
-        }
-    }
-
     xen_create_ioreq_server(xen_domid, &state->ioservid);
 
     state->exit.notify = xen_exit_notifier;
diff --git a/hw/xen/xen-common.c b/hw/xen/xen-common.c
index 83099dd..454777c 100644
--- a/hw/xen/xen-common.c
+++ b/hw/xen/xen-common.c
@@ -117,6 +117,19 @@ static void xen_change_state_handler(void *opaque, int running,
     }
 }
 
+static void xen_setup_post(MachineState *ms, AccelState *accel)
+{
+    int rc;
+
+    if (xen_domid_restrict) {
+        rc = xen_restrict(xen_domid);
+        if (rc < 0) {
+            perror("xen: failed to restrict");
+            exit(1);
+        }
+    }
+}
+
 static int xen_init(MachineState *ms)
 {
     xen_xc = xc_interface_open(0, 0, 0);
@@ -165,6 +178,7 @@ static void xen_accel_class_init(ObjectClass *oc, void *data)
     AccelClass *ac = ACCEL_CLASS(oc);
     ac->name = "Xen";
     ac->init_machine = xen_init;
+    ac->setup_post = xen_setup_post;
     ac->allowed = &xen_allowed;
     ac->global_props = xen_compat_props;
 }
-- 
2.1.4

[Qemu-devel] [PATCH 06/16] xen: destroy_hvm_domain: Move reason into a variable

[Ian Jackson]

We are going to want to reuse this.

No functional change.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
---
 hw/i386/xen/xen-hvm.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/hw/i386/xen/xen-hvm.c b/hw/i386/xen/xen-hvm.c
index 9c3b6b3..3590d99 100644
--- a/hw/i386/xen/xen-hvm.c
+++ b/hw/i386/xen/xen-hvm.c
@@ -1387,12 +1387,13 @@ void destroy_hvm_domain(bool reboot)
     xc_interface *xc_handle;
     int sts;
 
+    unsigned int reason = reboot ? SHUTDOWN_reboot : SHUTDOWN_poweroff;
+
     xc_handle = xc_interface_open(0, 0, 0);
     if (xc_handle == NULL) {
         fprintf(stderr, "Cannot acquire xenctrl handle\n");
     } else {
-        sts = xc_domain_shutdown(xc_handle, xen_domid,
-                                 reboot ? SHUTDOWN_reboot : SHUTDOWN_poweroff);
+        sts = xc_domain_shutdown(xc_handle, xen_domid, reason);
         if (sts != 0) {
             fprintf(stderr, "xc_domain_shutdown failed to issue %s, "
                     "sts %d, %s\n", reboot ? "reboot" : "poweroff",
-- 
2.1.4

[Qemu-devel] [PATCH 07/16] xen: move xc_interface compatibility fallback further up the file

[Ian Jackson]

We are going to want to use the dummy xendevicemodel_handle type in
new stub functions in the CONFIG_XEN_CTRL_INTERFACE_VERSION < 41000
section.  So we need to provide that definition, or (as applicable)
include the appropriate header, earlier in the file.

(Ideally the newer compatibility layers would be at the bottom of the
file, so that they can naturally benefit from the compatibility layers
for earlier version.  But that's rather too much for this series.)

No functional change.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
---
v2: New patch in v2 of the series
---
 include/hw/xen/xen_common.h | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/include/hw/xen/xen_common.h b/include/hw/xen/xen_common.h
index 1766bb9..60c4ebb 100644
--- a/include/hw/xen/xen_common.h
+++ b/include/hw/xen/xen_common.h
@@ -78,6 +78,17 @@ static inline void *xenforeignmemory_map(xc_interface *h, uint32_t dom,
 
 extern xenforeignmemory_handle *xen_fmem;
 
+#if CONFIG_XEN_CTRL_INTERFACE_VERSION < 40900
+
+typedef xc_interface xendevicemodel_handle;
+
+#else /* CONFIG_XEN_CTRL_INTERFACE_VERSION >= 40900 */
+
+#undef XC_WANT_COMPAT_DEVICEMODEL_API
+#include <xendevicemodel.h>
+
+#endif
+
 #if CONFIG_XEN_CTRL_INTERFACE_VERSION < 41000
 
 #define XEN_COMPAT_PHYSMAP
@@ -105,8 +116,6 @@ static inline int xentoolcore_restrict_all(domid_t domid)
 
 #if CONFIG_XEN_CTRL_INTERFACE_VERSION < 40900
 
-typedef xc_interface xendevicemodel_handle;
-
 static inline xendevicemodel_handle *xendevicemodel_open(
     struct xentoollog_logger *logger, unsigned int open_flags)
 {
@@ -228,11 +237,6 @@ static inline int xendevicemodel_set_mem_type(
     return xc_hvm_set_mem_type(dmod, domid, mem_type, first_pfn, nr);
 }
 
-#else /* CONFIG_XEN_CTRL_INTERFACE_VERSION >= 40900 */
-
-#undef XC_WANT_COMPAT_DEVICEMODEL_API
-#include <xendevicemodel.h>
-
 #endif
 
 extern xendevicemodel_handle *xen_dmod;
-- 
2.1.4

[Qemu-devel] [PATCH 08/16] xen: destroy_hvm_domain: Try xendevicemodel_shutdown

[Ian Jackson]

xc_interface_open etc. is not going to work if we have dropped
privilege, but xendevicemodel_shutdown will if everything is new
enough.

xendevicemodel_shutdown is only availabe in Xen 4.10 and later, so
provide a stub for earlier versions.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
---
v6.1: Fix { } style issue
v6: Do not print message about harmless condition in ENOTTY case.
v2: Add compatibility stub for Xen < 4.10.
    Fix coding style.
---
 hw/i386/xen/xen-hvm.c       | 12 ++++++++++++
 include/hw/xen/xen_common.h |  7 +++++++
 2 files changed, 19 insertions(+)

diff --git a/hw/i386/xen/xen-hvm.c b/hw/i386/xen/xen-hvm.c
index 3590d99..fb727bc 100644
--- a/hw/i386/xen/xen-hvm.c
+++ b/hw/i386/xen/xen-hvm.c
@@ -1386,9 +1386,21 @@ void destroy_hvm_domain(bool reboot)
 {
     xc_interface *xc_handle;
     int sts;
+    int rc;
 
     unsigned int reason = reboot ? SHUTDOWN_reboot : SHUTDOWN_poweroff;
 
+    if (xen_dmod) {
+        rc = xendevicemodel_shutdown(xen_dmod, xen_domid, reason);
+        if (!rc) {
+            return;
+        }
+        if (errno != ENOTTY /* old Xen */) {
+            perror("xendevicemodel_shutdown failed");
+        }
+        /* well, try the old thing then */
+    }
+
     xc_handle = xc_interface_open(0, 0, 0);
     if (xc_handle == NULL) {
         fprintf(stderr, "Cannot acquire xenctrl handle\n");
diff --git a/include/hw/xen/xen_common.h b/include/hw/xen/xen_common.h
index 60c4ebb..4bd30a3 100644
--- a/include/hw/xen/xen_common.h
+++ b/include/hw/xen/xen_common.h
@@ -108,6 +108,13 @@ static inline int xentoolcore_restrict_all(domid_t domid)
     return -1;
 }
 
+static inline int xendevicemodel_shutdown(xendevicemodel_handle *dmod,
+                                          domid_t domid, unsigned int reason)
+{
+    errno = ENOTTY;
+    return -1;
+}
+
 #else /* CONFIG_XEN_CTRL_INTERFACE_VERSION >= 41000 */
 
 #include <xentoolcore.h>
-- 
2.1.4

[Qemu-devel] [PATCH 09/16] os-posix: cleanup: Replace fprintfs with error_report in change_process_uid

[Ian Jackson]

I'm going to be editing this function and it makes sense to clean up
this style problem in advance.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
CC: Daniel P. Berrange <berrange@redhat.com>
CC: Michael Tokarev <mjt@tls.msk.ru>
---
 os-posix.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/os-posix.c b/os-posix.c
index b9c2343..560db95 100644
--- a/os-posix.c
+++ b/os-posix.c
@@ -167,20 +167,20 @@ static void change_process_uid(void)
 {
     if (user_pwd) {
         if (setgid(user_pwd->pw_gid) < 0) {
-            fprintf(stderr, "Failed to setgid(%d)\n", user_pwd->pw_gid);
+            error_report("Failed to setgid(%d)", user_pwd->pw_gid);
             exit(1);
         }
         if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) {
-            fprintf(stderr, "Failed to initgroups(\"%s\", %d)\n",
-                    user_pwd->pw_name, user_pwd->pw_gid);
+            error_report("Failed to initgroups(\"%s\", %d)",
+                         user_pwd->pw_name, user_pwd->pw_gid);
             exit(1);
         }
         if (setuid(user_pwd->pw_uid) < 0) {
-            fprintf(stderr, "Failed to setuid(%d)\n", user_pwd->pw_uid);
+            error_report("Failed to setuid(%d)", user_pwd->pw_uid);
             exit(1);
         }
         if (setuid(0) != -1) {
-            fprintf(stderr, "Dropping privileges failed\n");
+            error_report("Dropping privileges failed");
             exit(1);
         }
     }
-- 
2.1.4

Re: [Qemu-devel] [PATCH 09/16] os-posix: cleanup: Replace fprintfs with error_report in change_process_uid

[Peter Maydell]

On 24 April 2018 at 18:58, Ian Jackson <ian.jackson@eu.citrix.com> wrote:
> I'm going to be editing this function and it makes sense to clean up
> this style problem in advance.
>
> Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
> CC: Paolo Bonzini <pbonzini@redhat.com>
> CC: Markus Armbruster <armbru@redhat.com>
> CC: Daniel P. Berrange <berrange@redhat.com>
> CC: Michael Tokarev <mjt@tls.msk.ru>
> ---

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM

Re: [Qemu-devel] [PATCH 09/16] os-posix: cleanup: Replace fprintfs with error_report in change_process_uid

[Thomas Huth]

On 24.04.2018 19:58, Ian Jackson wrote:
> I'm going to be editing this function and it makes sense to clean up
> this style problem in advance.
> 
> Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
> CC: Paolo Bonzini <pbonzini@redhat.com>
> CC: Markus Armbruster <armbru@redhat.com>
> CC: Daniel P. Berrange <berrange@redhat.com>
> CC: Michael Tokarev <mjt@tls.msk.ru>
> ---
>  os-posix.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/os-posix.c b/os-posix.c
> index b9c2343..560db95 100644
> --- a/os-posix.c
> +++ b/os-posix.c
> @@ -167,20 +167,20 @@ static void change_process_uid(void)
>  {
>      if (user_pwd) {
>          if (setgid(user_pwd->pw_gid) < 0) {
> -            fprintf(stderr, "Failed to setgid(%d)\n", user_pwd->pw_gid);
> +            error_report("Failed to setgid(%d)", user_pwd->pw_gid);
>              exit(1);
>          }
>          if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) {
> -            fprintf(stderr, "Failed to initgroups(\"%s\", %d)\n",
> -                    user_pwd->pw_name, user_pwd->pw_gid);
> +            error_report("Failed to initgroups(\"%s\", %d)",
> +                         user_pwd->pw_name, user_pwd->pw_gid);
>              exit(1);
>          }
>          if (setuid(user_pwd->pw_uid) < 0) {
> -            fprintf(stderr, "Failed to setuid(%d)\n", user_pwd->pw_uid);
> +            error_report("Failed to setuid(%d)", user_pwd->pw_uid);
>              exit(1);
>          }
>          if (setuid(0) != -1) {
> -            fprintf(stderr, "Dropping privileges failed\n");
> +            error_report("Dropping privileges failed");
>              exit(1);
>          }
>      }
> 

Reviewed-by: Thomas Huth <thuth@redhat.com>

[Qemu-devel] [PATCH 10/16] os-posix: Provide new -runas <uid>:<gid> facility

[Ian Jackson]

This allows the caller to specify a uid and gid to use, even if there
is no corresponding password entry.  This will be useful in certain
Xen configurations.

We don't support just -runas <uid> because: (i) deprivileging without
calling setgroups would be ineffective (ii) given only a uid we don't
know what gid we ought to use (since uids may eppear in multiple
passwd file entries with different gids).

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
CC: Daniel P. Berrange <berrange@redhat.com>
CC: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
---
v7: Be much more explicit about legal combinations of user_{pwd,uid,gid}.
    Rely more on qemu_stroul being sane, dropping pointless
     pre-assignments of errno and lv.
    Retain optarg in error message about -runas argument.
    Rebase over introduction of error_report in change_process_uid.
v6.1: Fix constness of qemu_strtoul end pointer parameter.
v6: Use qemu_strtoul for the first strtoul.
    Use error_report rather than fprintf to print usage error message.
    Fix an error message which still referred to . rather than :
v5: Use : rather than . to separate uid from gid
v4: Changed to reuse option -runas
v3: Error messages fixed.  Thanks to Peter Maydell and Ross Lagerwall.
---
 os-posix.c      | 77 ++++++++++++++++++++++++++++++++++++++++++++++++---------
 qemu-options.hx |  3 ++-
 2 files changed, 67 insertions(+), 13 deletions(-)

diff --git a/os-posix.c b/os-posix.c
index 560db95..0f59566 100644
--- a/os-posix.c
+++ b/os-posix.c
@@ -41,7 +41,14 @@
 #include <sys/prctl.h>
 #endif
 
-static struct passwd *user_pwd;
+/*
+ * Must set all three of these at once.
+ * Legal combinations are              unset   by name   by uid
+ */
+static struct passwd *user_pwd;    /*   NULL   non-NULL   NULL   */
+static uid_t user_uid = (uid_t)-1; /*   -1      -1        >=0    */
+static gid_t user_gid = (gid_t)-1; /*   -1      -1        >=0    */
+
 static const char *chroot_dir;
 static int daemonize;
 static int daemon_pipe;
@@ -127,6 +134,33 @@ void os_set_proc_name(const char *s)
 #endif
 }
 
+
+static bool os_parse_runas_uid_gid(const char *optarg)
+{
+    unsigned long lv;
+    const char *ep;
+    uid_t got_uid;
+    gid_t got_gid;
+    int rc;
+
+    rc = qemu_strtoul(optarg, &ep, 0, &lv);
+    got_uid = lv; /* overflow here is ID in C99 */
+    if (rc || *ep != ':' || got_uid != lv || got_uid == (uid_t)-1) {
+        return false;
+    }
+
+    rc = qemu_strtoul(ep + 1, 0, 0, &lv);
+    got_gid = lv; /* overflow here is ID in C99 */
+    if (rc || got_gid != lv || got_gid == (gid_t)-1) {
+        return false;
+    }
+
+    user_pwd = NULL;
+    user_uid = got_uid;
+    user_gid = got_gid;
+    return true;
+}
+
 /*
  * Parse OS specific command line options.
  * return 0 if option handled, -1 otherwise
@@ -144,8 +178,13 @@ void os_parse_cmd_args(int index, const char *optarg)
 #endif
     case QEMU_OPTION_runas:
         user_pwd = getpwnam(optarg);
-        if (!user_pwd) {
-            fprintf(stderr, "User \"%s\" doesn't exist\n", optarg);
+        if (user_pwd) {
+            user_uid = -1;
+            user_gid = -1;
+        } else if (!os_parse_runas_uid_gid(optarg)) {
+            error_report("User \"%s\" doesn't exist"
+                         " (and is not <uid>:<gid>)",
+                         optarg);
             exit(1);
         }
         break;
@@ -165,18 +204,32 @@ void os_parse_cmd_args(int index, const char *optarg)
 
 static void change_process_uid(void)
 {
-    if (user_pwd) {
-        if (setgid(user_pwd->pw_gid) < 0) {
-            error_report("Failed to setgid(%d)", user_pwd->pw_gid);
+    assert((user_uid == (uid_t)-1) || user_pwd == NULL);
+    assert((user_uid == (uid_t)-1) ==
+           (user_gid == (gid_t)-1));
+
+    if (user_pwd || user_uid != (uid_t)-1) {
+        gid_t intended_gid = user_pwd ? user_pwd->pw_gid : user_gid;
+        uid_t intended_uid = user_pwd ? user_pwd->pw_uid : user_uid;
+        if (setgid(intended_gid) < 0) {
+            error_report("Failed to setgid(%d)", intended_gid);
             exit(1);
         }
-        if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) {
-            error_report("Failed to initgroups(\"%s\", %d)",
-                         user_pwd->pw_name, user_pwd->pw_gid);
-            exit(1);
+        if (user_pwd) {
+            if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) {
+                error_report("Failed to initgroups(\"%s\", %d)",
+                        user_pwd->pw_name, user_pwd->pw_gid);
+                exit(1);
+            }
+        } else {
+            if (setgroups(1, &user_gid) < 0) {
+                error_report("Failed to setgroups(1, [%d])",
+                        user_gid);
+                exit(1);
+            }
         }
-        if (setuid(user_pwd->pw_uid) < 0) {
-            error_report("Failed to setuid(%d)", user_pwd->pw_uid);
+        if (setuid(intended_uid) < 0) {
+            error_report("Failed to setuid(%d)", intended_uid);
             exit(1);
         }
         if (setuid(0) != -1) {
diff --git a/qemu-options.hx b/qemu-options.hx
index ca4e412..5fbf966 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3765,7 +3765,8 @@ ETEXI
 
 #ifndef _WIN32
 DEF("runas", HAS_ARG, QEMU_OPTION_runas, \
-    "-runas user     change to user id user just before starting the VM\n",
+    "-runas user     change to user id user just before starting the VM\n" \
+    "                user can be numeric uid:gid instead\n",
     QEMU_ARCH_ALL)
 #endif
 STEXI
-- 
2.1.4

[Qemu-devel] [PATCH 11/16] xen: Use newly added dmops for mapping VGA memory

[Ian Jackson]

From: Ross Lagerwall <ross.lagerwall@citrix.com>

Xen unstable (to be in 4.11) has two new dmops, relocate_memory and
pin_memory_cacheattr. Use these to set up the VGA memory, replacing the
previous calls to libxc. This allows the VGA console to work properly
when QEMU is running restricted (-xen-domid-restrict).

Wrapper functions are provided to allow QEMU to work with older versions
of Xen.

Tweak the error handling while making this change:
* Report pin_memory_cacheattr errors.
* Report errors even when DEBUG_HVM is not set. This is useful for
trying to understand why VGA is not working, since otherwise it just
fails silently.
* Fix the return values when an error occurs. The functions now
consistently return -1 and set errno.

CC: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
---
v6.1: Fix printf formats to match types in error_report messages
      Fix spurious \n in error_report messages
      Fix { } style issue
v6: New patch in this version of the series
---
 configure                   | 19 +++++++++++++++++
 hw/i386/xen/xen-hvm.c       | 50 ++++++++++++++++++++++++---------------------
 include/hw/xen/xen_common.h | 32 +++++++++++++++++++++++++++++
 3 files changed, 78 insertions(+), 23 deletions(-)

diff --git a/configure b/configure
index 5cf9dde..aa35aef 100755
--- a/configure
+++ b/configure
@@ -2221,6 +2221,25 @@ EOF
     # Xen unstable
     elif
         cat > $TMPC <<EOF &&
+#undef XC_WANT_COMPAT_DEVICEMODEL_API
+#define __XEN_TOOLS__
+#include <xendevicemodel.h>
+int main(void) {
+  xendevicemodel_handle *xd;
+
+  xd = xendevicemodel_open(0, 0);
+  xendevicemodel_pin_memory_cacheattr(xd, 0, 0, 0, 0);
+
+  return 0;
+}
+EOF
+        compile_prog "" "$xen_libs -lxendevicemodel $xen_stable_libs -lxentoolcore"
+      then
+      xen_stable_libs="-lxendevicemodel $xen_stable_libs -lxentoolcore"
+      xen_ctrl_version=41100
+      xen=yes
+    elif
+        cat > $TMPC <<EOF &&
 #undef XC_WANT_COMPAT_MAP_FOREIGN_API
 #include <xenforeignmemory.h>
 #include <xentoolcore.h>
diff --git a/hw/i386/xen/xen-hvm.c b/hw/i386/xen/xen-hvm.c
index fb727bc..caa563b 100644
--- a/hw/i386/xen/xen-hvm.c
+++ b/hw/i386/xen/xen-hvm.c
@@ -347,7 +347,7 @@ static int xen_add_to_physmap(XenIOState *state,
                               MemoryRegion *mr,
                               hwaddr offset_within_region)
 {
-    unsigned long i = 0;
+    unsigned long nr_pages;
     int rc = 0;
     XenPhysmap *physmap = NULL;
     hwaddr pfn, start_gpfn;
@@ -396,22 +396,26 @@ go_physmap:
 
     pfn = phys_offset >> TARGET_PAGE_BITS;
     start_gpfn = start_addr >> TARGET_PAGE_BITS;
-    for (i = 0; i < size >> TARGET_PAGE_BITS; i++) {
-        unsigned long idx = pfn + i;
-        xen_pfn_t gpfn = start_gpfn + i;
-
-        rc = xen_xc_domain_add_to_physmap(xen_xc, xen_domid, XENMAPSPACE_gmfn, idx, gpfn);
-        if (rc) {
-            DPRINTF("add_to_physmap MFN %"PRI_xen_pfn" to PFN %"
-                    PRI_xen_pfn" failed: %d (errno: %d)\n", idx, gpfn, rc, errno);
-            return -rc;
-        }
+    nr_pages = size >> TARGET_PAGE_BITS;
+    rc = xendevicemodel_relocate_memory(xen_dmod, xen_domid, nr_pages, pfn,
+                                        start_gpfn);
+    if (rc) {
+        int saved_errno = errno;
+
+        error_report("relocate_memory %lu pages from GFN %"HWADDR_PRIx
+                     " to GFN %"HWADDR_PRIx" failed: %s",
+                     nr_pages, pfn, start_gpfn, strerror(saved_errno));
+        errno = saved_errno;
+        return -1;
     }
 
-    xc_domain_pin_memory_cacheattr(xen_xc, xen_domid,
+    rc = xendevicemodel_pin_memory_cacheattr(xen_dmod, xen_domid,
                                    start_addr >> TARGET_PAGE_BITS,
                                    (start_addr + size - 1) >> TARGET_PAGE_BITS,
                                    XEN_DOMCTL_MEM_CACHEATTR_WB);
+    if (rc) {
+        error_report("pin_memory_cacheattr failed: %s", strerror(errno));
+    }
     return xen_save_physmap(state, physmap);
 }
 
@@ -419,7 +423,6 @@ static int xen_remove_from_physmap(XenIOState *state,
                                    hwaddr start_addr,
                                    ram_addr_t size)
 {
-    unsigned long i = 0;
     int rc = 0;
     XenPhysmap *physmap = NULL;
     hwaddr phys_offset = 0;
@@ -438,16 +441,17 @@ static int xen_remove_from_physmap(XenIOState *state,
     size >>= TARGET_PAGE_BITS;
     start_addr >>= TARGET_PAGE_BITS;
     phys_offset >>= TARGET_PAGE_BITS;
-    for (i = 0; i < size; i++) {
-        xen_pfn_t idx = start_addr + i;
-        xen_pfn_t gpfn = phys_offset + i;
-
-        rc = xen_xc_domain_add_to_physmap(xen_xc, xen_domid, XENMAPSPACE_gmfn, idx, gpfn);
-        if (rc) {
-            fprintf(stderr, "add_to_physmap MFN %"PRI_xen_pfn" to PFN %"
-                    PRI_xen_pfn" failed: %d (errno: %d)\n", idx, gpfn, rc, errno);
-            return -rc;
-        }
+    rc = xendevicemodel_relocate_memory(xen_dmod, xen_domid, size, start_addr,
+                                        phys_offset);
+    if (rc) {
+        int saved_errno = errno;
+
+        error_report("relocate_memory "RAM_ADDR_FMT" pages"
+                     " from GFN %"HWADDR_PRIx
+                     " to GFN %"HWADDR_PRIx" failed: %s",
+                     size, start_addr, phys_offset, strerror(saved_errno));
+        errno = saved_errno;
+        return -1;
     }
 
     QLIST_REMOVE(physmap, list);
diff --git a/include/hw/xen/xen_common.h b/include/hw/xen/xen_common.h
index 4bd30a3..2eed6fc 100644
--- a/include/hw/xen/xen_common.h
+++ b/include/hw/xen/xen_common.h
@@ -89,6 +89,38 @@ typedef xc_interface xendevicemodel_handle;
 
 #endif
 
+#if CONFIG_XEN_CTRL_INTERFACE_VERSION < 41100
+
+static inline int xendevicemodel_relocate_memory(
+    xendevicemodel_handle *dmod, domid_t domid, uint32_t size, uint64_t src_gfn,
+    uint64_t dst_gfn)
+{
+    uint32_t i;
+    int rc;
+
+    for (i = 0; i < size; i++) {
+        unsigned long idx = src_gfn + i;
+        xen_pfn_t gpfn = dst_gfn + i;
+
+        rc = xc_domain_add_to_physmap(xen_xc, domid, XENMAPSPACE_gmfn, idx,
+                                      gpfn);
+        if (rc) {
+            return rc;
+        }
+    }
+
+    return 0;
+}
+
+static inline int xendevicemodel_pin_memory_cacheattr(
+    xendevicemodel_handle *dmod, domid_t domid, uint64_t start, uint64_t end,
+    uint32_t type)
+{
+    return xc_domain_pin_memory_cacheattr(xen_xc, domid, start, end, type);
+}
+
+#endif /* CONFIG_XEN_CTRL_INTERFACE_VERSION < 41100 */
+
 #if CONFIG_XEN_CTRL_INTERFACE_VERSION < 41000
 
 #define XEN_COMPAT_PHYSMAP
-- 
2.1.4

[Qemu-devel] [PATCH 12/16] xen: Remove now-obsolete xen_xc_domain_add_to_physmap

[Ian Jackson]

The last user was just removed; remove this function, accordingly.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
---
 include/hw/xen/xen_common.h | 22 ----------------------
 1 file changed, 22 deletions(-)

diff --git a/include/hw/xen/xen_common.h b/include/hw/xen/xen_common.h
index 2eed6fc..5f1402b 100644
--- a/include/hw/xen/xen_common.h
+++ b/include/hw/xen/xen_common.h
@@ -645,28 +645,6 @@ static inline int xen_set_ioreq_server_state(domid_t dom,
 
 #endif
 
-#if CONFIG_XEN_CTRL_INTERFACE_VERSION < 40600
-static inline int xen_xc_domain_add_to_physmap(xc_interface *xch, uint32_t domid,
-                                               unsigned int space,
-                                               unsigned long idx,
-                                               xen_pfn_t gpfn)
-{
-    return xc_domain_add_to_physmap(xch, domid, space, idx, gpfn);
-}
-#else
-static inline int xen_xc_domain_add_to_physmap(xc_interface *xch, uint32_t domid,
-                                               unsigned int space,
-                                               unsigned long idx,
-                                               xen_pfn_t gpfn)
-{
-    /* In Xen 4.6 rc is -1 and errno contains the error value. */
-    int rc = xc_domain_add_to_physmap(xch, domid, space, idx, gpfn);
-    if (rc == -1)
-        return errno;
-    return rc;
-}
-#endif
-
 #ifdef CONFIG_XEN_PV_DOMAIN_BUILD
 #if CONFIG_XEN_CTRL_INTERFACE_VERSION < 40700
 static inline int xen_domain_create(xc_interface *xc, uint32_t ssidref,
-- 
2.1.4

[Qemu-devel] [PATCH 13/16] xen: Expect xenstore write to fail when restricted

[Ian Jackson]

From: Ross Lagerwall <ross.lagerwall@citrix.com>

Saving the current state to xenstore may fail when running restricted
(in particular, after a migration). Therefore, don't report the error or
exit when running restricted.  Toolstacks that want to allow running
QEMU restricted should instead make use of QMP events to listen for
state changes.

CC: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
---
v6: New patch in this version of the series
---
 hw/xen/xen-common.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/hw/xen/xen-common.c b/hw/xen/xen-common.c
index 454777c..6ec14c7 100644
--- a/hw/xen/xen-common.c
+++ b/hw/xen/xen-common.c
@@ -101,7 +101,12 @@ static void xenstore_record_dm_state(struct xs_handle *xs, const char *state)
     }
 
     snprintf(path, sizeof (path), "device-model/%u/state", xen_domid);
-    if (!xs_write(xs, XBT_NULL, path, state, strlen(state))) {
+    /*
+     * This call may fail when running restricted so don't make it fatal in
+     * that case. Toolstacks should instead use QMP to listen for state changes.
+     */
+    if (!xs_write(xs, XBT_NULL, path, state, strlen(state)) &&
+            !xen_domid_restrict) {
         error_report("error recording dm state");
         exit(1);
     }
-- 
2.1.4

[Qemu-devel] [PATCH 14/16] os-posix: cleanup: Replace fprintf with error_report in remaining call sites

[Ian Jackson]

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
CC: Daniel P. Berrange <berrange@redhat.com>
CC: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
v8: Remove one remaining spurious "\n"
v7: New patch
---
 os-posix.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/os-posix.c b/os-posix.c
index 0f59566..a2ba50d 100644
--- a/os-posix.c
+++ b/os-posix.c
@@ -129,7 +129,7 @@ void os_set_proc_name(const char *s)
         exit(1);
     }
 #else
-    fprintf(stderr, "Change of process name not supported by your OS\n");
+    error_report("Change of process name not supported by your OS");
     exit(1);
 #endif
 }
@@ -243,7 +243,7 @@ static void change_root(void)
 {
     if (chroot_dir) {
         if (chroot(chroot_dir) < 0) {
-            fprintf(stderr, "chroot failed\n");
+            error_report("chroot failed");
             exit(1);
         }
         if (chdir("/")) {
-- 
2.1.4

Re: [Qemu-devel] [PATCH 14/16] os-posix: cleanup: Replace fprintf with error_report in remaining call sites

[Thomas Huth]

On 24.04.2018 19:58, Ian Jackson wrote:
> Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
> CC: Paolo Bonzini <pbonzini@redhat.com>
> CC: Markus Armbruster <armbru@redhat.com>
> CC: Daniel P. Berrange <berrange@redhat.com>
> CC: Michael Tokarev <mjt@tls.msk.ru>
> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
> v8: Remove one remaining spurious "\n"
> v7: New patch
> ---
>  os-posix.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/os-posix.c b/os-posix.c
> index 0f59566..a2ba50d 100644
> --- a/os-posix.c
> +++ b/os-posix.c
> @@ -129,7 +129,7 @@ void os_set_proc_name(const char *s)
>          exit(1);
>      }
>  #else
> -    fprintf(stderr, "Change of process name not supported by your OS\n");
> +    error_report("Change of process name not supported by your OS");
>      exit(1);
>  #endif
>  }
> @@ -243,7 +243,7 @@ static void change_root(void)
>  {
>      if (chroot_dir) {
>          if (chroot(chroot_dir) < 0) {
> -            fprintf(stderr, "chroot failed\n");
> +            error_report("chroot failed");
>              exit(1);
>          }
>          if (chdir("/")) {
> 

Maybe merge this with patch 9/16?

Anyway:

Reviewed-by: Thomas Huth <thuth@redhat.com>

[Qemu-devel] [PATCH 15/16] os-posix: cleanup: Replace perror with error_report

[Ian Jackson]

perror() is defined to fprintf(stderr,...).  HACKING says
fprintf(stderr,...) is wrong.  So perror() is too.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
CC: Daniel P. Berrange <berrange@redhat.com>
CC: Michael Tokarev <mjt@tls.msk.ru>
CC: Alistair Francis <alistair.francis@xilinx.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
v7: New patch
---
 os-posix.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/os-posix.c b/os-posix.c
index a2ba50d..24eb700 100644
--- a/os-posix.c
+++ b/os-posix.c
@@ -125,7 +125,7 @@ void os_set_proc_name(const char *s)
     /* Could rewrite argv[0] too, but that's a bit more complicated.
        This simple way is enough for `top'. */
     if (prctl(PR_SET_NAME, name)) {
-        perror("unable to change process name");
+        error_report("unable to change process name: %s", strerror(errno));
         exit(1);
     }
 #else
@@ -247,7 +247,7 @@ static void change_root(void)
             exit(1);
         }
         if (chdir("/")) {
-            perror("not able to chdir to /");
+            error_report("not able to chdir to /: %s", strerror(errno));
             exit(1);
         }
     }
@@ -309,7 +309,7 @@ void os_setup_post(void)
 
     if (daemonize) {
         if (chdir("/")) {
-            perror("not able to chdir to /");
+            error_report("not able to chdir to /: %s", strerror(errno));
             exit(1);
         }
         TFR(fd = qemu_open("/dev/null", O_RDWR));
@@ -383,7 +383,7 @@ int os_mlock(void)
 
     ret = mlockall(MCL_CURRENT | MCL_FUTURE);
     if (ret < 0) {
-        perror("mlockall");
+        error_report("mlockall: %s", strerror(errno));
     }
 
     return ret;
-- 
2.1.4

Re: [Qemu-devel] [Xen-devel] [PATCH 15/16] os-posix: cleanup: Replace perror with error_report

[Alistair Francis]

On Tue, Apr 24, 2018 at 10:58 AM, Ian Jackson <ian.jackson@eu.citrix.com> wrote:
> perror() is defined to fprintf(stderr,...).  HACKING says
> fprintf(stderr,...) is wrong.  So perror() is too.
>
> Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
> CC: Paolo Bonzini <pbonzini@redhat.com>
> CC: Markus Armbruster <armbru@redhat.com>
> CC: Daniel P. Berrange <berrange@redhat.com>
> CC: Michael Tokarev <mjt@tls.msk.ru>
> CC: Alistair Francis <alistair.francis@xilinx.com>
> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
> v7: New patch
> ---
>  os-posix.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/os-posix.c b/os-posix.c
> index a2ba50d..24eb700 100644
> --- a/os-posix.c
> +++ b/os-posix.c
> @@ -125,7 +125,7 @@ void os_set_proc_name(const char *s)
>      /* Could rewrite argv[0] too, but that's a bit more complicated.
>         This simple way is enough for `top'. */
>      if (prctl(PR_SET_NAME, name)) {
> -        perror("unable to change process name");
> +        error_report("unable to change process name: %s", strerror(errno));
>          exit(1);
>      }
>  #else
> @@ -247,7 +247,7 @@ static void change_root(void)
>              exit(1);
>          }
>          if (chdir("/")) {
> -            perror("not able to chdir to /");
> +            error_report("not able to chdir to /: %s", strerror(errno));
>              exit(1);
>          }
>      }
> @@ -309,7 +309,7 @@ void os_setup_post(void)
>
>      if (daemonize) {
>          if (chdir("/")) {
> -            perror("not able to chdir to /");
> +            error_report("not able to chdir to /: %s", strerror(errno));
>              exit(1);
>          }
>          TFR(fd = qemu_open("/dev/null", O_RDWR));
> @@ -383,7 +383,7 @@ int os_mlock(void)
>
>      ret = mlockall(MCL_CURRENT | MCL_FUTURE);
>      if (ret < 0) {
> -        perror("mlockall");
> +        error_report("mlockall: %s", strerror(errno));
>      }
>
>      return ret;
> --
> 2.1.4
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xenproject.org
> https://lists.xenproject.org/mailman/listinfo/xen-devel

[Qemu-devel] [PATCH 16/16] configure: do_compiler: Dump some extra info under bash

[Ian Jackson]

This makes it much easier to find a particular thing in config.log.

We have to use the ${BASH_LINENO[*]} syntax which is a syntax error in
other shells, so test what shell we are running and use eval.

The extra output is only printed if configure is run with bash.  On
systems where /bin/sh is not bash, it is necessary to say bash
./configure to get the extra debug info in the log.

Suggested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Kent R. Spillner <kspillner@acm.org>
CC: Janosch Frank <frankja@linux.vnet.ibm.com>
CC: Thomas Huth <thuth@redhat.com>
CC: Peter Maydell <peter.maydell@linaro.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
---
v8: Fix so that it actually works as intended with bash.
v6: Fix commit message wording.
v4: No longer tag this patch RFC.
---
 configure | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/configure b/configure
index aa35aef..f9ba9ea 100755
--- a/configure
+++ b/configure
@@ -60,6 +60,11 @@ do_compiler() {
     # is compiler binary to execute.
     local compiler="$1"
     shift
+    if test -n "$BASH_VERSION"; then eval '
+        echo >>config.log "
+funcs: ${FUNCNAME[*]}
+lines: ${BASH_LINENO[*]}"
+    '; fi
     echo $compiler "$@" >> config.log
     $compiler "$@" >> config.log 2>&1 || return $?
     # Test passed. If this is an --enable-werror build, rerun
-- 
2.1.4

Re: [Qemu-devel] [PATCH 16/16] configure: do_compiler: Dump some extra info under bash

[Thomas Huth]

On 24.04.2018 19:58, Ian Jackson wrote:
> This makes it much easier to find a particular thing in config.log.
> 
> We have to use the ${BASH_LINENO[*]} syntax which is a syntax error in
> other shells, so test what shell we are running and use eval.
> 
> The extra output is only printed if configure is run with bash.  On
> systems where /bin/sh is not bash, it is necessary to say bash
> ./configure to get the extra debug info in the log.
> 
> Suggested-by: Eric Blake <eblake@redhat.com>
> Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
> CC: Kent R. Spillner <kspillner@acm.org>
> CC: Janosch Frank <frankja@linux.vnet.ibm.com>
> CC: Thomas Huth <thuth@redhat.com>
> CC: Peter Maydell <peter.maydell@linaro.org>
> CC: Paolo Bonzini <pbonzini@redhat.com>
> ---
> v8: Fix so that it actually works as intended with bash.
> v6: Fix commit message wording.
> v4: No longer tag this patch RFC.
> ---
>  configure | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/configure b/configure
> index aa35aef..f9ba9ea 100755
> --- a/configure
> +++ b/configure
> @@ -60,6 +60,11 @@ do_compiler() {
>      # is compiler binary to execute.
>      local compiler="$1"
>      shift
> +    if test -n "$BASH_VERSION"; then eval '
> +        echo >>config.log "
> +funcs: ${FUNCNAME[*]}
> +lines: ${BASH_LINENO[*]}"
> +    '; fi
>      echo $compiler "$@" >> config.log
>      $compiler "$@" >> config.log 2>&1 || return $?
>      # Test passed. If this is an --enable-werror build, rerun

I just applied the patch and had a look at config.log, and this looks
useful indeed.

Tested-by: Thomas Huth <thuth@redhat.com>

[Qemu-devel] [PATCH v7 00/16] xen: xen-domid-restrict improvements

[Ian Jackson]

This series provides necessary support for running qemu as a Xen
device model without power equivalent to root.  In particular, it
makes -xen-domid-restrict effective.

Compared to v7, it addresses review comments.  As a result, it has
grown a couple of new cleanup patches, including a few that I tacked
on the end which weren't strictly necessary but which I thought people
would appreciate.

  m    01/16 checkpatch: Add xendevicemodel_handle to the list of
  + r  02/16 AccelClass: Introduce accel_setup_post
     a 03/16 xen: link against xentoolcore
     a 04/16 xen: restrict: use xentoolcore_restrict_all
  * -  05/16 xen: defer call to xen_restrict until just before
     a 06/16 xen: destroy_hvm_domain: Move reason into a variable
     a 07/16 xen: move xc_interface compatibility fallback further
    r  08/16 xen: destroy_hvm_domain: Try xendevicemodel_shutdown
  +    09/16 os-posix: cleanup: Replace fprintfs with error_report
  m    10/16 os-posix: Provide new -runas <uid>:<gid> facility
     a 11/16 xen: Use newly added dmops for mapping VGA memory
       12/16 xen: Remove now-obsolete xen_xc_domain_add_to_physmap
     a 13/16 xen: Expect xenstore write to fail when restricted
  +    14/16 os-posix: cleanup: Replace fprintf with error_report in
  +    15/16 os-posix: cleanup: Replace perror with error_report
       16/16 configure: do_compiler: Dump some extra info under bash

 m = commit message (only) changed
 r = reviewed (by someone other than me)
 a = acked
 - = reviewed-by/acked-by dropped due to changes
 + = new patch
 * = amended patch

I'd particularly like to draw attention to what is now patch 12/16 and
16/16 which have been posted before but remained unreviewed.

Thanks for your attention.

Ian.

[Qemu-devel] [PATCH 11/16] xen: Use newly added dmops for mapping VGA memory

[Ian Jackson]

From: Ross Lagerwall <ross.lagerwall@citrix.com>

Xen unstable (to be in 4.11) has two new dmops, relocate_memory and
pin_memory_cacheattr. Use these to set up the VGA memory, replacing the
previous calls to libxc. This allows the VGA console to work properly
when QEMU is running restricted (-xen-domid-restrict).

Wrapper functions are provided to allow QEMU to work with older versions
of Xen.

Tweak the error handling while making this change:
* Report pin_memory_cacheattr errors.
* Report errors even when DEBUG_HVM is not set. This is useful for
trying to understand why VGA is not working, since otherwise it just
fails silently.
* Fix the return values when an error occurs. The functions now
consistently return -1 and set errno.

CC: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
---
v6.1: Fix printf formats to match types in error_report messages
      Fix spurious \n in error_report messages
      Fix { } style issue
v6: New patch in this version of the series
---
 configure                   | 19 +++++++++++++++++
 hw/i386/xen/xen-hvm.c       | 50 ++++++++++++++++++++++++---------------------
 include/hw/xen/xen_common.h | 32 +++++++++++++++++++++++++++++
 3 files changed, 78 insertions(+), 23 deletions(-)

diff --git a/configure b/configure
index f580255..d5435ff 100755
--- a/configure
+++ b/configure
@@ -2218,6 +2218,25 @@ EOF
     # Xen unstable
     elif
         cat > $TMPC <<EOF &&
+#undef XC_WANT_COMPAT_DEVICEMODEL_API
+#define __XEN_TOOLS__
+#include <xendevicemodel.h>
+int main(void) {
+  xendevicemodel_handle *xd;
+
+  xd = xendevicemodel_open(0, 0);
+  xendevicemodel_pin_memory_cacheattr(xd, 0, 0, 0, 0);
+
+  return 0;
+}
+EOF
+        compile_prog "" "$xen_libs -lxendevicemodel $xen_stable_libs -lxentoolcore"
+      then
+      xen_stable_libs="-lxendevicemodel $xen_stable_libs -lxentoolcore"
+      xen_ctrl_version=41100
+      xen=yes
+    elif
+        cat > $TMPC <<EOF &&
 #undef XC_WANT_COMPAT_MAP_FOREIGN_API
 #include <xenforeignmemory.h>
 #include <xentoolcore.h>
diff --git a/hw/i386/xen/xen-hvm.c b/hw/i386/xen/xen-hvm.c
index fb727bc..caa563b 100644
--- a/hw/i386/xen/xen-hvm.c
+++ b/hw/i386/xen/xen-hvm.c
@@ -347,7 +347,7 @@ static int xen_add_to_physmap(XenIOState *state,
                               MemoryRegion *mr,
                               hwaddr offset_within_region)
 {
-    unsigned long i = 0;
+    unsigned long nr_pages;
     int rc = 0;
     XenPhysmap *physmap = NULL;
     hwaddr pfn, start_gpfn;
@@ -396,22 +396,26 @@ go_physmap:
 
     pfn = phys_offset >> TARGET_PAGE_BITS;
     start_gpfn = start_addr >> TARGET_PAGE_BITS;
-    for (i = 0; i < size >> TARGET_PAGE_BITS; i++) {
-        unsigned long idx = pfn + i;
-        xen_pfn_t gpfn = start_gpfn + i;
-
-        rc = xen_xc_domain_add_to_physmap(xen_xc, xen_domid, XENMAPSPACE_gmfn, idx, gpfn);
-        if (rc) {
-            DPRINTF("add_to_physmap MFN %"PRI_xen_pfn" to PFN %"
-                    PRI_xen_pfn" failed: %d (errno: %d)\n", idx, gpfn, rc, errno);
-            return -rc;
-        }
+    nr_pages = size >> TARGET_PAGE_BITS;
+    rc = xendevicemodel_relocate_memory(xen_dmod, xen_domid, nr_pages, pfn,
+                                        start_gpfn);
+    if (rc) {
+        int saved_errno = errno;
+
+        error_report("relocate_memory %lu pages from GFN %"HWADDR_PRIx
+                     " to GFN %"HWADDR_PRIx" failed: %s",
+                     nr_pages, pfn, start_gpfn, strerror(saved_errno));
+        errno = saved_errno;
+        return -1;
     }
 
-    xc_domain_pin_memory_cacheattr(xen_xc, xen_domid,
+    rc = xendevicemodel_pin_memory_cacheattr(xen_dmod, xen_domid,
                                    start_addr >> TARGET_PAGE_BITS,
                                    (start_addr + size - 1) >> TARGET_PAGE_BITS,
                                    XEN_DOMCTL_MEM_CACHEATTR_WB);
+    if (rc) {
+        error_report("pin_memory_cacheattr failed: %s", strerror(errno));
+    }
     return xen_save_physmap(state, physmap);
 }
 
@@ -419,7 +423,6 @@ static int xen_remove_from_physmap(XenIOState *state,
                                    hwaddr start_addr,
                                    ram_addr_t size)
 {
-    unsigned long i = 0;
     int rc = 0;
     XenPhysmap *physmap = NULL;
     hwaddr phys_offset = 0;
@@ -438,16 +441,17 @@ static int xen_remove_from_physmap(XenIOState *state,
     size >>= TARGET_PAGE_BITS;
     start_addr >>= TARGET_PAGE_BITS;
     phys_offset >>= TARGET_PAGE_BITS;
-    for (i = 0; i < size; i++) {
-        xen_pfn_t idx = start_addr + i;
-        xen_pfn_t gpfn = phys_offset + i;
-
-        rc = xen_xc_domain_add_to_physmap(xen_xc, xen_domid, XENMAPSPACE_gmfn, idx, gpfn);
-        if (rc) {
-            fprintf(stderr, "add_to_physmap MFN %"PRI_xen_pfn" to PFN %"
-                    PRI_xen_pfn" failed: %d (errno: %d)\n", idx, gpfn, rc, errno);
-            return -rc;
-        }
+    rc = xendevicemodel_relocate_memory(xen_dmod, xen_domid, size, start_addr,
+                                        phys_offset);
+    if (rc) {
+        int saved_errno = errno;
+
+        error_report("relocate_memory "RAM_ADDR_FMT" pages"
+                     " from GFN %"HWADDR_PRIx
+                     " to GFN %"HWADDR_PRIx" failed: %s",
+                     size, start_addr, phys_offset, strerror(saved_errno));
+        errno = saved_errno;
+        return -1;
     }
 
     QLIST_REMOVE(physmap, list);
diff --git a/include/hw/xen/xen_common.h b/include/hw/xen/xen_common.h
index 4bd30a3..2eed6fc 100644
--- a/include/hw/xen/xen_common.h
+++ b/include/hw/xen/xen_common.h
@@ -89,6 +89,38 @@ typedef xc_interface xendevicemodel_handle;
 
 #endif
 
+#if CONFIG_XEN_CTRL_INTERFACE_VERSION < 41100
+
+static inline int xendevicemodel_relocate_memory(
+    xendevicemodel_handle *dmod, domid_t domid, uint32_t size, uint64_t src_gfn,
+    uint64_t dst_gfn)
+{
+    uint32_t i;
+    int rc;
+
+    for (i = 0; i < size; i++) {
+        unsigned long idx = src_gfn + i;
+        xen_pfn_t gpfn = dst_gfn + i;
+
+        rc = xc_domain_add_to_physmap(xen_xc, domid, XENMAPSPACE_gmfn, idx,
+                                      gpfn);
+        if (rc) {
+            return rc;
+        }
+    }
+
+    return 0;
+}
+
+static inline int xendevicemodel_pin_memory_cacheattr(
+    xendevicemodel_handle *dmod, domid_t domid, uint64_t start, uint64_t end,
+    uint32_t type)
+{
+    return xc_domain_pin_memory_cacheattr(xen_xc, domid, start, end, type);
+}
+
+#endif /* CONFIG_XEN_CTRL_INTERFACE_VERSION < 41100 */
+
 #if CONFIG_XEN_CTRL_INTERFACE_VERSION < 41000
 
 #define XEN_COMPAT_PHYSMAP
-- 
2.1.4