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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH V3] libxl: write IO ABI for disk frontends
This is a patch to forward-port a Xend behaviour. Xend writes IO ABI used for
all frontends. Blkfront before 2.6.26 relies on this behaviour otherwise guest
cannot boot when running in 32-on-64 mode. Blkfront after 2.6.26 writes that
node itself, in which case it's just an overwrite to an existing node which
should be OK.
In fact Xend writes the ABI for all frontends including console and vif. But
nowadays only old disk frontends rely on that behaviour so that we only write
the ABI for disk frontends in libxl, minimizing the impact.
Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Roger Pau Monne <roger.pau@xxxxxxxxxx>
Cc: Valtteri Kiviniemi <kiviniemi.valtteri@xxxxxxxxx>
---
tools/libxc/xc_dom_arm.c | 7 +++++++
tools/libxc/xc_dom_x86.c | 34 ++++++++++++++++++++++++++++++++++
tools/libxc/xenctrl.h | 10 ++++++++++
tools/libxl/libxl.c | 28 ++++++++++++++++++++++++++++
xen/include/public/io/protocols.h | 1 +
5 files changed, 80 insertions(+)
diff --git a/tools/libxc/xc_dom_arm.c b/tools/libxc/xc_dom_arm.c
index 041832e..aaf35ca 100644
--- a/tools/libxc/xc_dom_arm.c
+++ b/tools/libxc/xc_dom_arm.c
@@ -29,6 +29,13 @@
#define CONSOLE_PFN_OFFSET 0
#define XENSTORE_PFN_OFFSET 1
+/* get guest IO ABI protocol */
+const char *xc_domain_get_native_protocol(xc_interface *xch,
+ uint32_t domid)
+{
+ return XEN_IO_PROTO_ABI_ARM;
+}
+
/* ------------------------------------------------------------------------ */
/*
* arm guests are hybrid and start off with paging disabled, therefore no
diff --git a/tools/libxc/xc_dom_x86.c b/tools/libxc/xc_dom_x86.c
index eb9ac07..84a8de6 100644
--- a/tools/libxc/xc_dom_x86.c
+++ b/tools/libxc/xc_dom_x86.c
@@ -47,6 +47,40 @@
#define round_down(addr, mask) ((addr) & ~(mask))
#define round_up(addr, mask) ((addr) | (mask))
+/* get guest IO ABI protocol */
+const char *xc_domain_get_native_protocol(xc_interface *xch,
+ uint32_t domid)
+{
+ int ret;
+ uint32_t guest_width;
+ const char *protocol;
+ DECLARE_DOMCTL;
+
+ memset(&domctl, 0, sizeof(domctl));
+ domctl.domain = domid;
+ domctl.cmd = XEN_DOMCTL_get_address_size;
+
+ ret = do_domctl(xch, &domctl);
+
+ if ( ret )
+ return NULL;
+
+ guest_width = domctl.u.address_size.size;
+
+ switch (guest_width) {
+ case 32: /* 32 bit guest */
+ protocol = XEN_IO_PROTO_ABI_X86_32;
+ break;
+ case 64: /* 64 bit guest */
+ protocol = XEN_IO_PROTO_ABI_X86_64;
+ break;
+ default:
+ protocol = NULL;
+ }
+
+ return protocol;
+}
+
static unsigned long
nr_page_tables(struct xc_dom_image *dom,
xen_vaddr_t start, xen_vaddr_t end, unsigned long bits)
diff --git a/tools/libxc/xenctrl.h b/tools/libxc/xenctrl.h
index 50853af..2f32151 100644
--- a/tools/libxc/xenctrl.h
+++ b/tools/libxc/xenctrl.h
@@ -637,6 +637,16 @@ int xc_domain_hvm_setcontext(xc_interface *xch,
uint32_t size);
/**
+ * This function will return guest IO ABI protocol
+ *
+ * @parm xch a handle to an open hypervisor interface
+ * @parm domid the domain to get IO ABI protocol for
+ * @return guest protocol on success, NULL on failure
+ */
+const char *xc_domain_get_native_protocol(xc_interface *xch,
+ uint32_t domid);
+
+/**
* This function returns information about the execution context of a
* particular vcpu of a domain.
*
diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 572c2c6..550c63d 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -18,6 +18,8 @@
#include "libxl_internal.h"
+#include <xen/io/protocols.h>
+
#define PAGE_TO_MEMKB(pages) ((pages) * 4)
#define BACKEND_STRING_SIZE 5
@@ -2037,6 +2039,14 @@ static void device_disk_add(libxl__egc *egc, uint32_t
domid,
int rc;
libxl_ctx *ctx = gc->owner;
xs_transaction_t t = XBT_NULL;
+ const char *protocol = NULL;
+ char p[XEN_IO_PROTO_ABI_MAX_LEN+1];
+
+ libxl_domain_type type = libxl__domain_type(gc, domid);
+ if (type == LIBXL_DOMAIN_TYPE_INVALID) {
+ rc = ERROR_FAIL;
+ goto out;
+ }
for (;;) {
rc = libxl__xs_transaction_start(gc, &t);
@@ -2156,6 +2166,24 @@ static void device_disk_add(libxl__egc *egc, uint32_t
domid,
flexarray_append(front, "device-type");
flexarray_append(front, disk->is_cdrom ? "cdrom" : "disk");
+ /*
+ * Old PV kernel disk frontends before 2.6.26 rely on tool stack to
+ * write disk native protocol to frontend node. Xend does this, port
+ * this behaviour to xl.
+ *
+ * New kernels write this node themselves. In that case it just
+ * overwrites an existing node which is OK.
+ */
+ if (type == LIBXL_DOMAIN_TYPE_PV) {
+ protocol = xc_domain_get_native_protocol(ctx->xch, domid);
+ if (protocol) {
+ strncpy(p, protocol, strlen(protocol));
+ p[strlen(protocol)] = 0;
+ flexarray_append(front, "protocol");
+ flexarray_append(front, p);
+ }
+ }
+
libxl__device_generic_add(gc, t, device,
libxl__xs_kvs_of_flexarray(gc, back, back->count),
libxl__xs_kvs_of_flexarray(gc, front,
front->count));
diff --git a/xen/include/public/io/protocols.h
b/xen/include/public/io/protocols.h
index 80b196b..c2b949e 100644
--- a/xen/include/public/io/protocols.h
+++ b/xen/include/public/io/protocols.h
@@ -26,6 +26,7 @@
#define XEN_IO_PROTO_ABI_X86_32 "x86_32-abi"
#define XEN_IO_PROTO_ABI_X86_64 "x86_64-abi"
#define XEN_IO_PROTO_ABI_ARM "arm-abi"
+#define XEN_IO_PROTO_ABI_MAX_LEN 10 /* maximum length of above strings */
#if defined(__i386__)
# define XEN_IO_PROTO_ABI_NATIVE XEN_IO_PROTO_ABI_X86_32
--
1.7.10.4
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