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[5/7] tools/ocaml/xc: Fix binding for xc_domain_assign_device()

Message ID 20230131212913.6199-6-andrew.cooper3@citrix.com (mailing list archive)
State New, archived
Headers show
Series tools/ocaml: Memory corruption fixes in bindings | expand

Commit Message

Andrew Cooper Jan. 31, 2023, 9:29 p.m. UTC 
From: Edwin Török <edwin.torok@cloud.com>

The patch adding this binding was plain broken, and unreviewed.  It modified
the C stub to add a 4th parameter without an equivalent adjustment in the
Ocaml side of the bindings.

In 64bit builds, this causes us to dereference whatever dead value is in %rcx
when trying to interpret the rflags parameter.

This has gone unnoticed because Xapi doesn't use this binding (it has its
own), but unbreak the binding by passing RDM_RELAXED unconditionally for
now (matching the libxl default behaviour).

Fixes: 9b34056cb4 ("tools: extend xc_assign_device() to support rdm reservation policy")
Signed-off-by: Edwin Török <edwin.torok@cloud.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Christian Lindig <christian.lindig@citrix.com>
CC: David Scott <dave@recoil.org>
CC: Edwin Török <edwin.torok@cloud.com>
CC: Rob Hoes <Rob.Hoes@citrix.com>
---
 tools/ocaml/libs/xc/xenctrl_stubs.c | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)
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Patch

diff --git a/tools/ocaml/libs/xc/xenctrl_stubs.c b/tools/ocaml/libs/xc/xenctrl_stubs.c
index fd1f306f0202..291663bb278a 100644
--- a/tools/ocaml/libs/xc/xenctrl_stubs.c
+++ b/tools/ocaml/libs/xc/xenctrl_stubs.c
@@ -1245,17 +1245,12 @@  CAMLprim value stub_xc_domain_test_assign_device(value xch, value domid, value d
 	CAMLreturn(Val_bool(ret == 0));
 }
 
-static int domain_assign_device_rdm_flag_table[] = {
-    XEN_DOMCTL_DEV_RDM_RELAXED,
-};
-
-CAMLprim value stub_xc_domain_assign_device(value xch, value domid, value desc,
-                                            value rflag)
+CAMLprim value stub_xc_domain_assign_device(value xch, value domid, value desc)
 {
-	CAMLparam4(xch, domid, desc, rflag);
+	CAMLparam3(xch, domid, desc);
 	int ret;
 	int domain, bus, dev, func;
-	uint32_t sbdf, flag;
+	uint32_t sbdf;
 
 	domain = Int_val(Field(desc, 0));
 	bus = Int_val(Field(desc, 1));
@@ -1263,10 +1258,8 @@  CAMLprim value stub_xc_domain_assign_device(value xch, value domid, value desc,
 	func = Int_val(Field(desc, 3));
 	sbdf = encode_sbdf(domain, bus, dev, func);
 
-	ret = Int_val(Field(rflag, 0));
-	flag = domain_assign_device_rdm_flag_table[ret];
-
-	ret = xc_assign_device(_H(xch), _D(domid), sbdf, flag);
+	ret = xc_assign_device(_H(xch), _D(domid), sbdf,
+			       XEN_DOMCTL_DEV_RDM_RELAXED);
 
 	if (ret < 0)
 		failwith_xc(_H(xch));