[ipfire-2.x.git] / src / patches / suse-2.6.27.39 / patches.xen / xen-blkif-protocol-fallback-hack

Subject: 32-on-64 blkif protocol negotiation fallback for old guests.
From: kraxel@suse.de
References: 244055
Patch-mainline: never.

See the comment below.  Oh well.

---
 drivers/xen/blkback/xenbus.c |   10 +--
 drivers/xen/blktap/xenbus.c  |   10 +--
 drivers/xen/core/Makefile    |    2 
 drivers/xen/core/domctl.c    |  133 +++++++++++++++++++++++++++++++++++++++++++
 drivers/xen/core/domctl.h    |    2 
 5 files changed, 148 insertions(+), 9 deletions(-)

Index: head-2008-09-15/drivers/xen/blkback/xenbus.c
===================================================================
--- head-2008-09-15.orig/drivers/xen/blkback/xenbus.c	2008-09-15 15:10:36.000000000 +0200
+++ head-2008-09-15/drivers/xen/blkback/xenbus.c	2008-09-15 15:10:39.000000000 +0200
@@ -21,6 +21,7 @@
 #include <linux/module.h>
 #include <linux/kthread.h>
 #include "common.h"
+#include "../core/domctl.h"
 
 #undef DPRINTK
 #define DPRINTK(fmt, args...)				\
@@ -488,8 +489,10 @@ static int connect_ring(struct backend_i
 	be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
 	err = xenbus_gather(XBT_NIL, dev->otherend, "protocol",
 			    "%63s", protocol, NULL);
-	if (err)
-		strcpy(protocol, "unspecified, assuming native");
+	if (err) {
+		strcpy(protocol, "unspecified");
+		be->blkif->blk_protocol = xen_guest_blkif_protocol(be->blkif->domid);
+	}
 	else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE))
 		be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
 	else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32))
Index: head-2008-09-15/drivers/xen/blktap/xenbus.c
===================================================================
--- head-2008-09-15.orig/drivers/xen/blktap/xenbus.c	2008-09-15 15:10:36.000000000 +0200
+++ head-2008-09-15/drivers/xen/blktap/xenbus.c	2008-09-15 15:10:39.000000000 +0200
@@ -39,6 +39,7 @@
 #include <linux/kthread.h>
 #include <xen/xenbus.h>
 #include "common.h"
+#include "../core/domctl.h"
 
 
 struct backend_info
@@ -426,8 +427,10 @@ static int connect_ring(struct backend_i
 	be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
 	err = xenbus_gather(XBT_NIL, dev->otherend, "protocol",
 			    "%63s", protocol, NULL);
-	if (err)
-		strcpy(protocol, "unspecified, assuming native");
+	if (err) {
+		strcpy(protocol, "unspecified");
+		be->blkif->blk_protocol = xen_guest_blkif_protocol(be->blkif->domid);
+	}
 	else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE))
 		be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
 	else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32))
Index: head-2008-09-15/drivers/xen/core/Makefile
===================================================================
--- head-2008-09-15.orig/drivers/xen/core/Makefile	2008-09-15 14:45:31.000000000 +0200
+++ head-2008-09-15/drivers/xen/core/Makefile	2008-09-15 15:10:39.000000000 +0200
@@ -2,7 +2,7 @@
 # Makefile for the linux kernel.
 #
 
-obj-y := evtchn.o gnttab.o features.o reboot.o machine_reboot.o firmware.o
+obj-y := evtchn.o gnttab.o features.o reboot.o machine_reboot.o firmware.o domctl.o
 
 obj-$(CONFIG_PCI)		+= pci.o
 obj-$(CONFIG_PROC_FS)		+= xen_proc.o
Index: head-2008-09-15/drivers/xen/core/domctl.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ head-2008-09-15/drivers/xen/core/domctl.c	2008-09-15 15:10:39.000000000 +0200
@@ -0,0 +1,113 @@
+/*
+ * !!!  dirty hack alert  !!!
+ *
+ * Problem: old guests kernels don't have a "protocol" node
+ *          in the frontend xenstore directory, so mixing
+ *          32 and 64bit domains doesn't work.
+ *
+ * Upstream plans to solve this in the tools, by letting them
+ * create a protocol node.  Which certainly makes sense.
+ * But it isn't trivial and isn't done yet.  Too bad.
+ *
+ * So for the time being we use the get_address_size domctl
+ * hypercall for a pretty good guess.  Not nice as the domctl
+ * hypercall isn't supposed to be used by the kernel.  Because
+ * we don't want to have dependencies between dom0 kernel and
+ * xen kernel versions.  Now we have one.  Ouch.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <asm/hypervisor.h>
+#include <xen/blkif.h>
+
+#include "domctl.h"
+
+/* stuff copied from xen/interface/domctl.h, which we can't
+ * include directly for the reasons outlined above .... */
+
+#define XEN_DOMCTL_get_address_size 36
+typedef struct xen_domctl_address_size {
+	uint32_t size;
+} xen_domctl_address_size_t;
+
+typedef __attribute__((aligned(8))) uint64_t uint64_aligned_t;
+
+union xen_domctl {
+	/* v4: sles10 sp1: xen 3.0.4 + 32-on-64 patches */
+	struct {
+		uint32_t cmd;
+		uint32_t interface_version;
+		domid_t  domain;
+		union {
+			/* left out lots of other struct xen_domctl_foobar */
+			struct xen_domctl_address_size       address_size;
+			uint64_t                             dummy_align;
+			uint8_t                              dummy_pad[128];
+		} u;
+	} v4;
+
+	/* v5: upstream: xen 3.1 */
+	struct {
+		uint32_t cmd;
+		uint32_t interface_version;
+		domid_t  domain;
+		union {
+			struct xen_domctl_address_size       address_size;
+			uint64_aligned_t                     dummy_align;
+			uint8_t                              dummy_pad[128];
+		} u;
+	} v5;
+};
+
+/* The actual code comes here */
+
+static inline int hypervisor_domctl(void *domctl)
+{
+	return _hypercall1(int, domctl, domctl);
+}
+
+int xen_guest_address_size(int domid)
+{
+	union xen_domctl domctl;
+	int low, ret;
+
+#define guest_address_size(ver) do {					\
+	memset(&domctl, 0, sizeof(domctl));				\
+	domctl.v##ver.cmd = XEN_DOMCTL_get_address_size;		\
+	domctl.v##ver.interface_version = low = ver;			\
+	domctl.v##ver.domain = domid;					\
+	ret = hypervisor_domctl(&domctl) ?: domctl.v##ver.u.address_size.size; \
+	if (ret == 32 || ret == 64) {					\
+		printk("v" #ver " domctl worked ok: dom%d is %d-bit\n",	\
+		       domid, ret);					\
+		return ret;						\
+	}								\
+} while (0)
+
+	guest_address_size(5);
+#if CONFIG_XEN_COMPAT < 0x030100
+	guest_address_size(4);
+#endif
+
+	ret = BITS_PER_LONG;
+	printk("v%d...5 domctls failed, assuming dom%d is native: %d\n",
+	       low, domid, ret);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(xen_guest_address_size);
+
+int xen_guest_blkif_protocol(int domid)
+{
+	int address_size = xen_guest_address_size(domid);
+
+	if (address_size == BITS_PER_LONG)
+		return BLKIF_PROTOCOL_NATIVE;
+	if (address_size == 32)
+		return BLKIF_PROTOCOL_X86_32;
+	if (address_size == 64)
+		return BLKIF_PROTOCOL_X86_64;
+	return BLKIF_PROTOCOL_NATIVE;
+}
+EXPORT_SYMBOL_GPL(xen_guest_blkif_protocol);
Index: head-2008-09-15/drivers/xen/core/domctl.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ head-2008-09-15/drivers/xen/core/domctl.h	2008-09-15 15:10:39.000000000 +0200
@@ -0,0 +1,2 @@
+int xen_guest_address_size(int domid);
+int xen_guest_blkif_protocol(int domid);
Commit	Line	Data
2cb7cef9 BS	1	Subject: 32-on-64 blkif protocol negotiation fallback for old guests.
	2	From: kraxel@suse.de
	3	References: 244055
	4	Patch-mainline: never.
	5
	6	See the comment below. Oh well.
	7
	8	---
	9	drivers/xen/blkback/xenbus.c \| 10 +--
	10	drivers/xen/blktap/xenbus.c \| 10 +--
	11	drivers/xen/core/Makefile \| 2
	12	drivers/xen/core/domctl.c \| 133 +++++++++++++++++++++++++++++++++++++++++++
	13	drivers/xen/core/domctl.h \| 2
	14	5 files changed, 148 insertions(+), 9 deletions(-)
	15
	16	Index: head-2008-09-15/drivers/xen/blkback/xenbus.c
	17	===================================================================
	18	--- head-2008-09-15.orig/drivers/xen/blkback/xenbus.c 2008-09-15 15:10:36.000000000 +0200
	19	+++ head-2008-09-15/drivers/xen/blkback/xenbus.c 2008-09-15 15:10:39.000000000 +0200
	20	@@ -21,6 +21,7 @@
	21	#include <linux/module.h>
	22	#include <linux/kthread.h>
	23	#include "common.h"
	24	+#include "../core/domctl.h"
	25
	26	#undef DPRINTK
	27	#define DPRINTK(fmt, args...) \
	28	@@ -488,8 +489,10 @@ static int connect_ring(struct backend_i
	29	be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
	30	err = xenbus_gather(XBT_NIL, dev->otherend, "protocol",
	31	"%63s", protocol, NULL);
	32	- if (err)
	33	- strcpy(protocol, "unspecified, assuming native");
	34	+ if (err) {
	35	+ strcpy(protocol, "unspecified");
	36	+ be->blkif->blk_protocol = xen_guest_blkif_protocol(be->blkif->domid);
	37	+ }
	38	else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE))
	39	be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
	40	else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32))
	41	Index: head-2008-09-15/drivers/xen/blktap/xenbus.c
	42	===================================================================
	43	--- head-2008-09-15.orig/drivers/xen/blktap/xenbus.c 2008-09-15 15:10:36.000000000 +0200
	44	+++ head-2008-09-15/drivers/xen/blktap/xenbus.c 2008-09-15 15:10:39.000000000 +0200
	45	@@ -39,6 +39,7 @@
	46	#include <linux/kthread.h>
	47	#include <xen/xenbus.h>
	48	#include "common.h"
	49	+#include "../core/domctl.h"
	50
	51
	52	struct backend_info
	53	@@ -426,8 +427,10 @@ static int connect_ring(struct backend_i
	54	be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
	55	err = xenbus_gather(XBT_NIL, dev->otherend, "protocol",
	56	"%63s", protocol, NULL);
	57	- if (err)
	58	- strcpy(protocol, "unspecified, assuming native");
	59	+ if (err) {
	60	+ strcpy(protocol, "unspecified");
	61	+ be->blkif->blk_protocol = xen_guest_blkif_protocol(be->blkif->domid);
	62	+ }
	63	else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE))
	64	be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
65	else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32))
66	Index: head-2008-09-15/drivers/xen/core/Makefile
67	===================================================================
68	--- head-2008-09-15.orig/drivers/xen/core/Makefile 2008-09-15 14:45:31.000000000 +0200
69	+++ head-2008-09-15/drivers/xen/core/Makefile 2008-09-15 15:10:39.000000000 +0200
70	@@ -2,7 +2,7 @@
71	# Makefile for the linux kernel.
72	#
73
74	-obj-y := evtchn.o gnttab.o features.o reboot.o machine_reboot.o firmware.o
75	+obj-y := evtchn.o gnttab.o features.o reboot.o machine_reboot.o firmware.o domctl.o
76
77	obj-$(CONFIG_PCI) += pci.o
78	obj-$(CONFIG_PROC_FS) += xen_proc.o
79	Index: head-2008-09-15/drivers/xen/core/domctl.c
80	===================================================================
81	--- /dev/null 1970-01-01 00:00:00.000000000 +0000
82	+++ head-2008-09-15/drivers/xen/core/domctl.c 2008-09-15 15:10:39.000000000 +0200
83	@@ -0,0 +1,113 @@
84	+/*
85	+ * !!! dirty hack alert !!!
86	+ *
87	+ * Problem: old guests kernels don't have a "protocol" node
88	+ * in the frontend xenstore directory, so mixing
89	+ * 32 and 64bit domains doesn't work.
90	+ *
91	+ * Upstream plans to solve this in the tools, by letting them
92	+ * create a protocol node. Which certainly makes sense.
93	+ * But it isn't trivial and isn't done yet. Too bad.
94	+ *
95	+ * So for the time being we use the get_address_size domctl
96	+ * hypercall for a pretty good guess. Not nice as the domctl
97	+ * hypercall isn't supposed to be used by the kernel. Because
98	+ * we don't want to have dependencies between dom0 kernel and
99	+ * xen kernel versions. Now we have one. Ouch.
100	+ */
101	+
102	+#include <linux/kernel.h>
103	+#include <linux/module.h>
104	+#include <asm/hypervisor.h>
105	+#include <xen/blkif.h>
106	+
107	+#include "domctl.h"
108	+
109	+/* stuff copied from xen/interface/domctl.h, which we can't
110	+ * include directly for the reasons outlined above .... */
111	+
112	+#define XEN_DOMCTL_get_address_size 36
113	+typedef struct xen_domctl_address_size {
114	+ uint32_t size;
115	+} xen_domctl_address_size_t;
116	+
117	+typedef __attribute__((aligned(8))) uint64_t uint64_aligned_t;
118	+
119	+union xen_domctl {
120	+ /* v4: sles10 sp1: xen 3.0.4 + 32-on-64 patches */
121	+ struct {
122	+ uint32_t cmd;
123	+ uint32_t interface_version;
124	+ domid_t domain;
125	+ union {
126	+ /* left out lots of other struct xen_domctl_foobar */
127	+ struct xen_domctl_address_size address_size;
128	+ uint64_t dummy_align;
129	+ uint8_t dummy_pad[128];
130	+ } u;
131	+ } v4;
132	+
133	+ /* v5: upstream: xen 3.1 */
134	+ struct {
135	+ uint32_t cmd;
136	+ uint32_t interface_version;
137	+ domid_t domain;
138	+ union {
139	+ struct xen_domctl_address_size address_size;
140	+ uint64_aligned_t dummy_align;
141	+ uint8_t dummy_pad[128];
142	+ } u;
143	+ } v5;
144	+};
145	+
146	+/* The actual code comes here */
147	+
148	+static inline int hypervisor_domctl(void *domctl)
149	+{
150	+ return _hypercall1(int, domctl, domctl);
151	+}
152	+
153	+int xen_guest_address_size(int domid)
154	+{
155	+ union xen_domctl domctl;
156	+ int low, ret;
157	+
158	+#define guest_address_size(ver) do { \
159	+ memset(&domctl, 0, sizeof(domctl)); \
160	+ domctl.v##ver.cmd = XEN_DOMCTL_get_address_size; \
161	+ domctl.v##ver.interface_version = low = ver; \
162	+ domctl.v##ver.domain = domid; \
163	+ ret = hypervisor_domctl(&domctl) ?: domctl.v##ver.u.address_size.size; \
164	+ if (ret == 32 \|\| ret == 64) { \
165	+ printk("v" #ver " domctl worked ok: dom%d is %d-bit\n", \
166	+ domid, ret); \
167	+ return ret; \
168	+ } \
169	+} while (0)
170	+
171	+ guest_address_size(5);
172	+#if CONFIG_XEN_COMPAT < 0x030100
173	+ guest_address_size(4);
174	+#endif
175	+
176	+ ret = BITS_PER_LONG;
177	+ printk("v%d...5 domctls failed, assuming dom%d is native: %d\n",
178	+ low, domid, ret);
179	+
180	+ return ret;
181	+}
182	+EXPORT_SYMBOL_GPL(xen_guest_address_size);
183	+
184	+int xen_guest_blkif_protocol(int domid)
185	+{
186	+ int address_size = xen_guest_address_size(domid);
187	+
188	+ if (address_size == BITS_PER_LONG)
189	+ return BLKIF_PROTOCOL_NATIVE;
190	+ if (address_size == 32)
191	+ return BLKIF_PROTOCOL_X86_32;
192	+ if (address_size == 64)
193	+ return BLKIF_PROTOCOL_X86_64;
194	+ return BLKIF_PROTOCOL_NATIVE;
195	+}
196	+EXPORT_SYMBOL_GPL(xen_guest_blkif_protocol);
197	Index: head-2008-09-15/drivers/xen/core/domctl.h
198	===================================================================
199	--- /dev/null 1970-01-01 00:00:00.000000000 +0000
200	+++ head-2008-09-15/drivers/xen/core/domctl.h 2008-09-15 15:10:39.000000000 +0200
201	@@ -0,0 +1,2 @@
202	+int xen_guest_address_size(int domid);
203	+int xen_guest_blkif_protocol(int domid);