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[Qemu-devel] [PATCH for-2.8 07/38] s390x/css: handle cssid 255 correctly
From: |
Cornelia Huck |
Subject: |
[Qemu-devel] [PATCH for-2.8 07/38] s390x/css: handle cssid 255 correctly |
Date: |
Mon, 29 Aug 2016 13:44:59 +0200 |
The cssid 255 is reserved but still valid from an architectural
point of view. However, feeding a bogus schid of 0xffffffff into
the virtio hypercall will lead to a crash:
Stack trace of thread 138363:
#0 0x00000000100d168c css_find_subch (qemu-system-s390x)
#1 0x00000000100d3290 virtio_ccw_hcall_notify
#2 0x00000000100cbf60 s390_virtio_hypercall
#3 0x000000001010ff7a handle_hypercall
#4 0x0000000010079ed4 kvm_cpu_exec (qemu-system-s390x)
#5 0x00000000100609b4 qemu_kvm_cpu_thread_fn
#6 0x000003ff8b887bb4 start_thread (libpthread.so.0)
#7 0x000003ff8b78df0a thread_start (libc.so.6)
This is because the css array was only allocated for 0..254
instead of 0..255.
Let's fix this by bumping MAX_CSSID to 255 and fencing off the
reserved cssid of 255 during css image allocation.
Reported-by: Christian Borntraeger <address@hidden>
Tested-by: Christian Borntraeger <address@hidden>
Cc: address@hidden
Signed-off-by: Cornelia Huck <address@hidden>
---
hw/s390x/css.c | 8 +++-----
include/hw/s390x/css.h | 2 +-
2 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/hw/s390x/css.c b/hw/s390x/css.c
index bb8e4be..b0e81ef 100644
--- a/hw/s390x/css.c
+++ b/hw/s390x/css.c
@@ -141,7 +141,8 @@ out_err:
int css_create_css_image(uint8_t cssid, bool default_image)
{
trace_css_new_image(cssid, default_image ? "(default)" : "");
- if (cssid > MAX_CSSID) {
+ /* 255 is reserved */
+ if (cssid == 255) {
return -EINVAL;
}
if (channel_subsys.css[cssid]) {
@@ -1267,7 +1268,7 @@ bool css_schid_final(int m, uint8_t cssid, uint8_t ssid,
uint16_t schid)
uint8_t real_cssid;
real_cssid = (!m && (cssid == 0)) ? channel_subsys.default_cssid : cssid;
- if (real_cssid > MAX_CSSID || ssid > MAX_SSID ||
+ if (ssid > MAX_SSID ||
!channel_subsys.css[real_cssid] ||
!channel_subsys.css[real_cssid]->sch_set[ssid]) {
return true;
@@ -1282,9 +1283,6 @@ static int css_add_virtual_chpid(uint8_t cssid, uint8_t
chpid, uint8_t type)
CssImage *css;
trace_css_chpid_add(cssid, chpid, type);
- if (cssid > MAX_CSSID) {
- return -EINVAL;
- }
css = channel_subsys.css[cssid];
if (!css) {
return -EINVAL;
diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h
index 1da63e3..c96c862 100644
--- a/include/hw/s390x/css.h
+++ b/include/hw/s390x/css.h
@@ -20,7 +20,7 @@
#define MAX_DEVNO 65535
#define MAX_SCHID 65535
#define MAX_SSID 3
-#define MAX_CSSID 254 /* 255 is reserved */
+#define MAX_CSSID 255
#define MAX_CHPID 255
#define MAX_CIWS 62
--
2.9.3
- [Qemu-devel] [PATCH for-2.8 00/38] s390x patches for 2.8, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 03/38] s390x/pci: assert zpci always existing, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 10/38] qmp: details about CPU definitions in query-cpu-definitions, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 23/38] s390x/sclp: introduce sclp feature blocks, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 14/38] s390x/cpumodel: generate CPU feature lists for CPU models, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 04/38] s390/sclp: cache the sclp device, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 05/38] s390x: wrap flic savevm calls into vmstate, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 07/38] s390x/css: handle cssid 255 correctly,
Cornelia Huck <=
- [Qemu-devel] [PATCH for-2.8 16/38] s390x/cpumodel: introduce CPU feature group definitions, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 01/38] s390x: add compat machine for 2.8, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 26/38] s390x/sclp: propagate the mha via sclp, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 17/38] s390x/cpumodel: register defined CPU models as subclasses, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 25/38] s390x/sclp: propagate the ibc val (lowest and unblocked ibc), Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 21/38] s390x/cpumodel: check and apply the CPU model, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 06/38] s390x/ioinst: advertise fcs facility, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 38/38] s390x/cpumodel: implement QMP interface "query-cpu-model-baseline", Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 12/38] s390x/cpumodel: expose CPU class properties, Cornelia Huck, 2016/08/29
- [Qemu-devel] [PATCH for-2.8 20/38] s390x/cpumodel: let the CPU model handle feature checks, Cornelia Huck, 2016/08/29