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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] Re: Linux Stubdom Problem
2011/8/19 Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>:
> On Mon, 15 Aug 2011, Jiageng Yu wrote:
>> Hi Stefano,
>>
>> Â Â In the linux-pv xenfbfront driver, the vram is allocated by:
>> Â Â xenfb_probe()
>> Â Â Â Â ->info->fb = vmalloc(fb_size);
>>
>> Â Â In the linux-stubdom, the memory areas: (info->fb,
>> info->fb+fb_size) in linux-pv kernel, (s->vram_offset,
>> s->vram_offset+VGA_RAM_SIZE) in vga_common_init function,
>> (s->vram_ptr, s->vram_ptr+VGA_RAM_SIZE) in stubdom. These memory areas
>> should be mapped into the same machine memory region.
>>
>> Â Â But the (info->fb, info->fb+fb_size) in linux-pv kernel is
>> allocated independently. I have two optional plans to slove the
>> problem.
>>
>> 1. Modify linux-pv kernel.
>> Â Â This plan is more closer to the minios stubdom. First, I delay the
>> initial process of xenfbfront driver until qemu allocates s->vram_ptr.
>> Then, I set info->fb = s->vram_ptr.
>>
>> 2. Modify libxc.
>> Â Â The s->vram_ptr is generated by mmap() function in
>> linux_privcmd_map_foreign_bulk(). Maybe I could replace the return
>> value of mmap() with the info->fb, which is obtained from xenstore.
>
> you would also need to modify qemu_ram_alloc to make sure the same pages
> are remapped into the guest as videoram
>
>
>> Â Â Can these plans solve the problem? Or there is the better one?
>
> I think it is best to keep the memory allocation in xenfbfront as it is
> and find a way to map the pages in qemu. Isn't possible to use a mmap on
> the fbdev device to obtain a mapping of the vmalloc'ed area into qemu?
> Once we have mapped the pages into qemu address space it is just a
> matter of using them as videoram. ÂOtherwise you would have timing
> issues because qemu is probably going to start after xenfbfront has
> already allocated the buffer and enstablished a connection with the
> backend.
>
> In any case why don't you try running a guest without a video card (the
> qemu command line option for that is -vga none or -nographic) and see if
> everything else works?
>
Hi Stefano,
I am trying to fix the vram mapping issue. That is my new patch.
It is still needed to debug. Please check it for me and make sure I am
running on the right way.
I define a new enmu type Stubdom_Vga_State which is used to notify
xen_remap_bucket whether to map the vram memory. In
fbdev_pv_display_prepare function, I map the xen_fbfront memory to
qemu (fb_mem) and directly incoke ioctl(fd, IOCTL_PRIVCMD_MMAPBATCH,
&ioctlx) to map the vram of hvm guest.
diff --git a/fbdev.c b/fbdev.c
index a601b48..f7ff682 100644
--- a/fbdev.c
+++ b/fbdev.c
@@ -30,6 +30,12 @@
#include "sysemu.h"
#include "pflib.h"
+#include "hw/xen_backend.h"
+#include <xen/hvm/params.h>
+#include <sys/ioctl.h>
+#include "xenctrlosdep.h"
+#include <xen/privcmd.h>
+
/* -------------------------------------------------------------------- */
/* file handles */
@@ -541,29 +547,23 @@ static void fbdev_cleanup(void)
}
}
-static int fbdev_init(const char *device)
+static int fbdev_init(int prot, unsigned long size)
{
struct vt_stat vts;
unsigned long page_mask;
char ttyname[32];
/* open framebuffer */
- if (device == NULL) {
- device = getenv("FRAMEBUFFER");
- }
- if (device == NULL) {
- device = "/dev/fb0";
- }
- fb = open(device, O_RDWR);
+ fb = open("/dev/fb0", O_RDWR);
if (fb == -1) {
- fprintf(stderr, "open %s: %s\n", device, strerror(errno));
+ fprintf(stderr, "open /dev/fb0: %s\n", strerror(errno));
return -1;
}
/* open virtual console */
tty = 0;
if (ioctl(tty, VT_GETSTATE, &vts) < 0) {
fprintf(stderr, "Not started from virtual terminal, trying to
open one.\n");
snprintf(ttyname, sizeof(ttyname), "/dev/tty0");
tty = open(ttyname, O_RDWR);
@@ -632,14 +632,14 @@ static int fbdev_init(const char *device)
goto err;
}
page_mask = getpagesize()-1;
fb_mem_offset = (unsigned long)(fb_fix.smem_start) & page_mask;
- fb_mem = mmap(NULL,fb_fix.smem_len+fb_mem_offset,
- PROT_READ|PROT_WRITE,MAP_SHARED,fb,0);
+ fb_mem = mmap(NULL, size << XC_PAGE_SHIFT, prot, MAP_SHARED, fb, 0);
if (fb_mem == MAP_FAILED) {
perror("mmap");
goto err;
}
+
/* move viewport to upper left corner */
if (fb_var.xoffset != 0 || fb_var.yoffset != 0) {
fb_var.xoffset = 0;
@@ -930,3 +928,71 @@ void fbdev_display_uninit(void)
qemu_remove_exit_notifier(&exit_notifier);
uninit_mouse();
}
+
+int fbdev_pv_display_prepare(unsigned long domid, int prot, const
unsigned long *arr,
+ int *err,
unsigned int num)
+{
+ xen_pfn_t *pfn;
+ privcmd_mmapbatch_t ioctlx;
+ int fd,i,rc;
+
+ if (fbdev_init(prot,num) != 0) {
+ exit(1);
+ }
+
+ pfn = malloc(num * sizeof(*pfn));
+ if(!pfn){
+ errno = -ENOMEM;
+ rc = -1;
+ return rc;
+ }
+ memcpy(pfn, arr, num*sizeof(*arr));
+
+ fd = open("/proc/xen/privcmd", O_RDWR);
+ if(fd == -1){
+ fprintf(stderr,"Could not obtain handle on privcmd device\n");
+ exit(1);
+ }
+
+ ioctlx.num = num;
+ ioctlx.dom = domid;
+ ioctlx.addr = (unsigned long)fb_mem;
+ ioctlx.arr = pfn;
+
+ rc = ioctl(fd, IOCTL_PRIVCMD_MMAPBATCH, &ioctlx);
+
+ for(i=0; i<num; i++)
+ {
+ switch(pfn[i] ^ arr[i])
+ {
+ case 0:
+ err[i] = rc != -ENOENT ? rc:0;
+ continue;
+ default:
+ err[i] = -EINVAL;
+ continue;
+ }
+ break;
+ }
+
+ free(pfn);
+
+ if (rc == -ENOENT && i == num)
+ rc=0;
+ else if(rc)
+ {
+ errno = -rc;
+ rc = -1;
+ }
+
+ if(rc < 0)
+ {
+ fprintf(stderr,"privcmd ioctl failed\n");
+ munmap(fb_mem, num << XC_PAGE_SHIFT);
+ return NULL;
+ }
+
+ close(fd);
+
+ return fb_mem;
+}
diff --git a/hw/vga.c b/hw/vga.c
index 0f54734..de7dd85 100644
--- a/hw/vga.c
+++ b/hw/vga.c
@@ -28,6 +28,7 @@
#include "vga_int.h"
#include "pixel_ops.h"
#include "qemu-timer.h"
+#include "xen_backend.h"
//#define DEBUG_VGA
//#define DEBUG_VGA_MEM
@@ -2237,7 +2238,12 @@ void vga_common_init(VGACommonState *s, int vga_ram_size)
s->is_vbe_vmstate = 0;
#endif
s->vram_offset = qemu_ram_alloc(NULL, "vga.vram", vga_ram_size);
+#ifdef CONFIG_STUBDOM
+ stubdom_vga_state = VGA_INIT_READY;
+#endif
s->vram_ptr = qemu_get_ram_ptr(s->vram_offset);
s->vram_size = vga_ram_size;
s->get_bpp = vga_get_bpp;
s->get_offsets = vga_get_offsets;
diff --git a/hw/xen_backend.c b/hw/xen_backend.c
index c506dfe..f4ecce4 100644
--- a/hw/xen_backend.c
+++ b/hw/xen_backend.c
@@ -48,6 +48,10 @@ XenGnttab xen_xcg = XC_HANDLER_INITIAL_VALUE;
struct xs_handle *xenstore = NULL;
const char *xen_protocol;
+#ifdef CONFIG_STUBDOM
+enum Stubdom_Vga_State stubdom_vga_state=0;
+#endif
+
/* private */
static QTAILQ_HEAD(XenDeviceHead, XenDevice) xendevs =
QTAILQ_HEAD_INITIALIZER(xendevs);
static int debug = 0;
diff --git a/hw/xen_backend.h b/hw/xen_backend.h
index 3305630..36167d1 100644
--- a/hw/xen_backend.h
+++ b/hw/xen_backend.h
@@ -60,6 +60,16 @@ extern XenXC xen_xc;
extern struct xs_handle *xenstore;
extern const char *xen_protocol;
+#ifdef CONFIG_STUBDOM
+/* linux stubdom vga initialization*/
+enum Stubdom_Vga_State{
+ VGA_INIT_WAIT = 0,
+ VGA_INIT_READY,
+ VGA_INIT_COMPLETE
+};
+extern enum Stubdom_Vga_State stubdom_vga_state;
+#endif
+
/* xenstore helper functions */
int xenstore_write_str(const char *base, const char *node, const char *val);
int xenstore_write_int(const char *base, const char *node, int ival);
diff --git a/xen-mapcache.c b/xen-mapcache.c
index 007136a..e615f98 100644
--- a/xen-mapcache.c
+++ b/xen-mapcache.c
@@ -20,6 +20,7 @@
#include "xen-mapcache.h"
#include "trace.h"
+#include "hw/xen.h"
//#define MAPCACHE_DEBUG
@@ -144,8 +145,19 @@ static void xen_remap_bucket(MapCacheEntry *entry,
pfns[i] = (address_index << (MCACHE_BUCKET_SHIFT-XC_PAGE_SHIFT)) + i;
}
+#ifdef CONFIG_STUBDOM
+ if(stubdom_vga_state == VGA_INIT_READY){
+ fprintf(stderr,"xen_remap_bucket: start linux stubdom vga\n");
+ vaddr_base = fbdev_pv_display_prepare(xen_domid,
PROT_READ|PROT_WRITE,
+
pfns, err, nb_pfn);
+ stubdom_vga_state = VGA_INIT_COMPLETE;
+ }else
+ vaddr_base = xc_map_foreign_bulk(xen_xc, xen_domid,
PROT_READ|PROT_WRITE,
+ pfns, err, nb_pfn);
+#else
vaddr_base = xc_map_foreign_bulk(xen_xc, xen_domid, PROT_READ|PROT_WRITE,
pfns, err, nb_pfn);
+#endif
if (vaddr_base == NULL) {
perror("xc_map_foreign_bulk");
exit(-1);
Through I try to avoid modifing any code of linux-pv kernel, I
still have to commente out some code to make it run.
diff --git a/drivers/xen/xenfs/privcmd.c b/drivers/xen/xenfs/privcmd.c
index f80be7f..420f3b1 100644
--- a/drivers/xen/xenfs/privcmd.c
+++ b/drivers/xen/xenfs/privcmd.c
@@ -303,11 +309,10 @@ static long privcmd_ioctl_mmap_batch(void __user *udata)
vma = find_vma(mm, m.addr);
ret = -EINVAL;
+
if (!vma ||
- vma->vm_ops != &privcmd_vm_ops ||
(m.addr != vma->vm_start) ||
- ((m.addr + (nr_pages << PAGE_SHIFT)) != vma->vm_end) ||
- !privcmd_enforce_singleshot_mapping(vma)) {
+ ((m.addr + (nr_pages << PAGE_SHIFT)) != vma->vm_end)) {
up_write(&mm->mmap_sem);
goto out;
}
The debug dump of qemu is:
(XEN) mm.c:945:d51 Error getting mfn 8ed68 (pfn 18000) from L1 entry
800000008ed68625 for l1e_owner=51, pg_owner=51
(XEN) mm.c:5044:d51 ptwr_emulate: fixing up invalid PAE PTE 800000008ed68625
(XEN) mm.c:945:d51 Error getting mfn 8ed68 (pfn 18000) from L1 entry
800000008ed68667 for l1e_owner=51, pg_owner=51
(XEN) mm.c:5049:d51 ptwr_emulate: could not get_page_from_l1e()
<1>BUG: unable to handle kernel <c>paging request<c> at c1f1b8f8
<1>IP: [<c011a7f0>] ptep_set_access_flags+0x40/0x80
*pdpt = 0000000001ee2001 <c>*pde = 0000000000008067 *pte = 8000000001f1b061
<0>Oops: 0003 [#1]
<0>last sysfs file: /sys/devices/virtual/vc/vcsa1/dev
Pid: 283, comm: qemu Not tainted (2.6.32.41 #6)
EIP: 0061:[<c011a7f0>] EFLAGS: 00010202 CPU: 0
EIP is at ptep_set_access_flags+0x40/0x80
That seems the mapping is failed. (pfn 18000) is the first vram
page in hvm guest.
Jiageng Yu.
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