| Message ID | 20210413080745.33004-2-wangyanan55@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | hw/arm/virt: Introduce cpu topology support | expand |
On Tue, Apr 13, 2021 at 04:07:40PM +0800, Yanan Wang wrote: > From: Andrew Jones <drjones@redhat.com> > > qemu_fdt_add_path() works like qemu_fdt_add_subnode(), except > it also adds any missing subnodes in the path. We also tweak > an error message of qemu_fdt_add_subnode(). > > We'll make use of this new function in a coming patch. > > Signed-off-by: Andrew Jones <drjones@redhat.com> > Signed-off-by: Yanan Wang <wangyanan55@huawei.com> > --- > include/sysemu/device_tree.h | 1 + > softmmu/device_tree.c | 45 ++++++++++++++++++++++++++++++++++-- > 2 files changed, 44 insertions(+), 2 deletions(-) > > diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h > index 8a2fe55622..ef060a9759 100644 > --- a/include/sysemu/device_tree.h > +++ b/include/sysemu/device_tree.h > @@ -121,6 +121,7 @@ uint32_t qemu_fdt_get_phandle(void *fdt, const char *path); > uint32_t qemu_fdt_alloc_phandle(void *fdt); > int qemu_fdt_nop_node(void *fdt, const char *node_path); > int qemu_fdt_add_subnode(void *fdt, const char *name); > +int qemu_fdt_add_path(void *fdt, const char *path); > > #define qemu_fdt_setprop_cells(fdt, node_path, property, ...) \ > do { \ > diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c > index 2691c58cf6..8592c7aa1b 100644 > --- a/softmmu/device_tree.c > +++ b/softmmu/device_tree.c > @@ -541,8 +541,8 @@ int qemu_fdt_add_subnode(void *fdt, const char *name) > > retval = fdt_add_subnode(fdt, parent, basename); > if (retval < 0) { > - error_report("FDT: Failed to create subnode %s: %s", name, > - fdt_strerror(retval)); > + error_report("%s: Failed to create subnode %s: %s", > + __func__, name, fdt_strerror(retval)); > exit(1); > } > > @@ -550,6 +550,47 @@ int qemu_fdt_add_subnode(void *fdt, const char *name) > return retval; > } > > +/* > + * Like qemu_fdt_add_subnode(), but will add all missing > + * subnodes in the path. > + */ > +int qemu_fdt_add_path(void *fdt, const char *path) > +{ > + char *dupname, *basename, *p; > + int parent, retval = -1; > + > + if (path[0] != '/') { > + return retval; > + } > + > + parent = fdt_path_offset(fdt, "/"); Getting the offset for "/" is never needed - it's always 0. > + p = dupname = g_strdup(path); You shouldn't need the strdup(), see below. > + > + while (p) { > + *p = '/'; > + basename = p + 1; > + p = strchr(p + 1, '/'); > + if (p) { > + *p = '\0'; > + } > + retval = fdt_path_offset(fdt, dupname); The fdt_path_offset_namelen() function exists *exactly* so that you can look up partial parths without having to mangle your input string. Just set the namelen right, and it will ignore anything to the right of that. > + if (retval < 0 && retval != -FDT_ERR_NOTFOUND) { > + error_report("%s: Invalid path %s: %s", > + __func__, path, fdt_strerror(retval)); If you're getting an error other than FDT_ERR_NOTFOUND here, chances are it's not an invalid path, but a corrupted fdt blob or something else. > + exit(1); > + } else if (retval == -FDT_ERR_NOTFOUND) { > + retval = fdt_add_subnode(fdt, parent, basename); > + if (retval < 0) { > + break; > + } > + } > + parent = retval; > + } > + > + g_free(dupname); > + return retval; > +} > + > void qemu_fdt_dumpdtb(void *fdt, int size) > { > const char *dumpdtb = current_machine->dumpdtb;
Hi David, On 2021/4/16 12:52, David Gibson wrote: > On Tue, Apr 13, 2021 at 04:07:40PM +0800, Yanan Wang wrote: >> From: Andrew Jones <drjones@redhat.com> >> >> qemu_fdt_add_path() works like qemu_fdt_add_subnode(), except >> it also adds any missing subnodes in the path. We also tweak >> an error message of qemu_fdt_add_subnode(). >> >> We'll make use of this new function in a coming patch. >> >> Signed-off-by: Andrew Jones <drjones@redhat.com> >> Signed-off-by: Yanan Wang <wangyanan55@huawei.com> >> --- >> include/sysemu/device_tree.h | 1 + >> softmmu/device_tree.c | 45 ++++++++++++++++++++++++++++++++++-- >> 2 files changed, 44 insertions(+), 2 deletions(-) >> >> diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h >> index 8a2fe55622..ef060a9759 100644 >> --- a/include/sysemu/device_tree.h >> +++ b/include/sysemu/device_tree.h >> @@ -121,6 +121,7 @@ uint32_t qemu_fdt_get_phandle(void *fdt, const char *path); >> uint32_t qemu_fdt_alloc_phandle(void *fdt); >> int qemu_fdt_nop_node(void *fdt, const char *node_path); >> int qemu_fdt_add_subnode(void *fdt, const char *name); >> +int qemu_fdt_add_path(void *fdt, const char *path); >> >> #define qemu_fdt_setprop_cells(fdt, node_path, property, ...) \ >> do { \ >> diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c >> index 2691c58cf6..8592c7aa1b 100644 >> --- a/softmmu/device_tree.c >> +++ b/softmmu/device_tree.c >> @@ -541,8 +541,8 @@ int qemu_fdt_add_subnode(void *fdt, const char *name) >> >> retval = fdt_add_subnode(fdt, parent, basename); >> if (retval < 0) { >> - error_report("FDT: Failed to create subnode %s: %s", name, >> - fdt_strerror(retval)); >> + error_report("%s: Failed to create subnode %s: %s", >> + __func__, name, fdt_strerror(retval)); >> exit(1); >> } >> >> @@ -550,6 +550,47 @@ int qemu_fdt_add_subnode(void *fdt, const char *name) >> return retval; >> } >> >> +/* >> + * Like qemu_fdt_add_subnode(), but will add all missing >> + * subnodes in the path. >> + */ >> +int qemu_fdt_add_path(void *fdt, const char *path) >> +{ >> + char *dupname, *basename, *p; >> + int parent, retval = -1; >> + >> + if (path[0] != '/') { >> + return retval; >> + } >> + >> + parent = fdt_path_offset(fdt, "/"); > Getting the offset for "/" is never needed - it's always 0. Thanks, will fix it. >> + p = dupname = g_strdup(path); > You shouldn't need the strdup(), see below. > >> + >> + while (p) { >> + *p = '/'; >> + basename = p + 1; >> + p = strchr(p + 1, '/'); >> + if (p) { >> + *p = '\0'; >> + } >> + retval = fdt_path_offset(fdt, dupname); > The fdt_path_offset_namelen() function exists *exactly* so that you > can look up partial parths without having to mangle your input > string. Just set the namelen right, and it will ignore anything to > the right of that. Function fdt_path_offset_namelen() seems more reasonable. After we call qemu_fdt_add_path() to add "/cpus/cpu-map/socket0/core0" successfully, if we want to add another path like "/cpus/cpu-map/socket0/core1" we will get the error -FDT_ERR_NOTFOUND for each partial path. But actually "/cpus/cpu-map/socket0" already exists, so by using fdt_path_offset_namelen() with right namelen we can avoid the error retval for this part. >> + if (retval < 0 && retval != -FDT_ERR_NOTFOUND) { >> + error_report("%s: Invalid path %s: %s", >> + __func__, path, fdt_strerror(retval)); > If you're getting an error other than FDT_ERR_NOTFOUND here, chances > are it's not an invalid path, but a corrupted fdt blob or something > else. Right, there can be variable reasons for the fail in addition to the invalid path. >> + exit(1); >> + } else if (retval == -FDT_ERR_NOTFOUND) { >> + retval = fdt_add_subnode(fdt, parent, basename); >> + if (retval < 0) { >> + break; >> + } I found another question here. If path "/cpus/cpu-map/socket0/core0" has already been added, when we want to add another path "/cpus/cpu-map/socket0/core1" and go here with retval = fdt_add_subnode(fdt, parent, "cpus"), then retval will be -FDT_ERR_EXISTS, but we can't just break the loop in this case. Am I right of the explanation ? Thanks, Yanan >> + } >> + parent = retval; >> + } >> + >> + g_free(dupname); >> + return retval; >> +} >> + >> void qemu_fdt_dumpdtb(void *fdt, int size) >> { >> const char *dumpdtb = current_machine->dumpdtb;
On Sat, Apr 17, 2021 at 10:36:20AM +0800, wangyanan (Y) wrote: > Hi David, > > On 2021/4/16 12:52, David Gibson wrote: > > On Tue, Apr 13, 2021 at 04:07:40PM +0800, Yanan Wang wrote: > > > From: Andrew Jones <drjones@redhat.com> > > > > > > qemu_fdt_add_path() works like qemu_fdt_add_subnode(), except > > > it also adds any missing subnodes in the path. We also tweak > > > an error message of qemu_fdt_add_subnode(). > > > > > > We'll make use of this new function in a coming patch. > > > > > > Signed-off-by: Andrew Jones <drjones@redhat.com> > > > Signed-off-by: Yanan Wang <wangyanan55@huawei.com> > > > --- > > > include/sysemu/device_tree.h | 1 + > > > softmmu/device_tree.c | 45 ++++++++++++++++++++++++++++++++++-- > > > 2 files changed, 44 insertions(+), 2 deletions(-) > > > > > > diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h > > > index 8a2fe55622..ef060a9759 100644 > > > --- a/include/sysemu/device_tree.h > > > +++ b/include/sysemu/device_tree.h > > > @@ -121,6 +121,7 @@ uint32_t qemu_fdt_get_phandle(void *fdt, const char *path); > > > uint32_t qemu_fdt_alloc_phandle(void *fdt); > > > int qemu_fdt_nop_node(void *fdt, const char *node_path); > > > int qemu_fdt_add_subnode(void *fdt, const char *name); > > > +int qemu_fdt_add_path(void *fdt, const char *path); > > > #define qemu_fdt_setprop_cells(fdt, node_path, property, ...) \ > > > do { \ > > > diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c > > > index 2691c58cf6..8592c7aa1b 100644 > > > --- a/softmmu/device_tree.c > > > +++ b/softmmu/device_tree.c > > > @@ -541,8 +541,8 @@ int qemu_fdt_add_subnode(void *fdt, const char *name) > > > retval = fdt_add_subnode(fdt, parent, basename); > > > if (retval < 0) { > > > - error_report("FDT: Failed to create subnode %s: %s", name, > > > - fdt_strerror(retval)); > > > + error_report("%s: Failed to create subnode %s: %s", > > > + __func__, name, fdt_strerror(retval)); > > > exit(1); > > > } > > > @@ -550,6 +550,47 @@ int qemu_fdt_add_subnode(void *fdt, const char *name) > > > return retval; > > > } > > > +/* > > > + * Like qemu_fdt_add_subnode(), but will add all missing > > > + * subnodes in the path. > > > + */ > > > +int qemu_fdt_add_path(void *fdt, const char *path) > > > +{ > > > + char *dupname, *basename, *p; > > > + int parent, retval = -1; > > > + > > > + if (path[0] != '/') { > > > + return retval; > > > + } > > > + > > > + parent = fdt_path_offset(fdt, "/"); > > Getting the offset for "/" is never needed - it's always 0. > Thanks, will fix it. > > > + p = dupname = g_strdup(path); > > You shouldn't need the strdup(), see below. > > > > > + > > > + while (p) { > > > + *p = '/'; > > > + basename = p + 1; > > > + p = strchr(p + 1, '/'); > > > + if (p) { > > > + *p = '\0'; > > > + } > > > + retval = fdt_path_offset(fdt, dupname); > > The fdt_path_offset_namelen() function exists *exactly* so that you > > can look up partial parths without having to mangle your input > > string. Just set the namelen right, and it will ignore anything to > > the right of that. > Function fdt_path_offset_namelen() seems more reasonable. > > After we call qemu_fdt_add_path() to add "/cpus/cpu-map/socket0/core0" > successfully, > if we want to add another path like "/cpus/cpu-map/socket0/core1" we will > get the error > -FDT_ERR_NOTFOUND for each partial path. But actually > "/cpus/cpu-map/socket0" > already exists, so by using fdt_path_offset_namelen() with right namelen we > can avoid > the error retval for this part. I don't quite follow what you're saying here. AFAICT your logic was correct - it just involved a lot of mangling the given path (adding and removing \0s) which becomes unnecessary with fdt_path_offset_namelen(). > > > + if (retval < 0 && retval != -FDT_ERR_NOTFOUND) { > > > + error_report("%s: Invalid path %s: %s", > > > + __func__, path, fdt_strerror(retval)); > > If you're getting an error other than FDT_ERR_NOTFOUND here, chances > > are it's not an invalid path, but a corrupted fdt blob or something > > else. > > Right, there can be variable reasons for the fail in addition to the invalid > path. > > > > + exit(1); > > > + } else if (retval == -FDT_ERR_NOTFOUND) { > > > + retval = fdt_add_subnode(fdt, parent, basename); > > > + if (retval < 0) { > > > + break; > > > + } > I found another question here. If path "/cpus/cpu-map/socket0/core0" has > already > been added, when we want to add another path "/cpus/cpu-map/socket0/core1" > and go here with retval = fdt_add_subnode(fdt, parent, "cpus"), then retval > will > be -FDT_ERR_EXISTS, but we can't just break the loop in this case. > > Am I right of the explanation ? Not exactly. If you called that fdt_add_subnode() in that case you would get FDT_ERR_EXISTS. However, because the previous fdt_path_offset() has returned -FDT_ERR_NOTFOUND, you've already established that the partial path doesn't exist, so if you got an FDT_ERR_EXISTS here something has gone very strangely wrong (such as concurrent access to the flat tree, which would very likely corrupt it). Note that the repeated use of fdt_path_offset() in this function will repeatedly rescan the whole fdt from the beginning. If you're concerned about performance (which you might well not be), then a more efficient approach would be to take your input path component by component and use fdt_subnode_offset() directly.
Hi David, On 2021/4/19 9:13, David Gibson wrote: > On Sat, Apr 17, 2021 at 10:36:20AM +0800, wangyanan (Y) wrote: >> Hi David, >> >> On 2021/4/16 12:52, David Gibson wrote: >>> On Tue, Apr 13, 2021 at 04:07:40PM +0800, Yanan Wang wrote: >>>> From: Andrew Jones <drjones@redhat.com> >>>> >>>> qemu_fdt_add_path() works like qemu_fdt_add_subnode(), except >>>> it also adds any missing subnodes in the path. We also tweak >>>> an error message of qemu_fdt_add_subnode(). >>>> >>>> We'll make use of this new function in a coming patch. >>>> >>>> Signed-off-by: Andrew Jones <drjones@redhat.com> >>>> Signed-off-by: Yanan Wang <wangyanan55@huawei.com> >>>> --- >>>> include/sysemu/device_tree.h | 1 + >>>> softmmu/device_tree.c | 45 ++++++++++++++++++++++++++++++++++-- >>>> 2 files changed, 44 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h >>>> index 8a2fe55622..ef060a9759 100644 >>>> --- a/include/sysemu/device_tree.h >>>> +++ b/include/sysemu/device_tree.h >>>> @@ -121,6 +121,7 @@ uint32_t qemu_fdt_get_phandle(void *fdt, const char *path); >>>> uint32_t qemu_fdt_alloc_phandle(void *fdt); >>>> int qemu_fdt_nop_node(void *fdt, const char *node_path); >>>> int qemu_fdt_add_subnode(void *fdt, const char *name); >>>> +int qemu_fdt_add_path(void *fdt, const char *path); >>>> #define qemu_fdt_setprop_cells(fdt, node_path, property, ...) \ >>>> do { \ >>>> diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c >>>> index 2691c58cf6..8592c7aa1b 100644 >>>> --- a/softmmu/device_tree.c >>>> +++ b/softmmu/device_tree.c >>>> @@ -541,8 +541,8 @@ int qemu_fdt_add_subnode(void *fdt, const char *name) >>>> retval = fdt_add_subnode(fdt, parent, basename); >>>> if (retval < 0) { >>>> - error_report("FDT: Failed to create subnode %s: %s", name, >>>> - fdt_strerror(retval)); >>>> + error_report("%s: Failed to create subnode %s: %s", >>>> + __func__, name, fdt_strerror(retval)); >>>> exit(1); >>>> } >>>> @@ -550,6 +550,47 @@ int qemu_fdt_add_subnode(void *fdt, const char *name) >>>> return retval; >>>> } >>>> +/* >>>> + * Like qemu_fdt_add_subnode(), but will add all missing >>>> + * subnodes in the path. >>>> + */ >>>> +int qemu_fdt_add_path(void *fdt, const char *path) >>>> +{ >>>> + char *dupname, *basename, *p; >>>> + int parent, retval = -1; >>>> + >>>> + if (path[0] != '/') { >>>> + return retval; >>>> + } >>>> + >>>> + parent = fdt_path_offset(fdt, "/"); >>> Getting the offset for "/" is never needed - it's always 0. >> Thanks, will fix it. >>>> + p = dupname = g_strdup(path); >>> You shouldn't need the strdup(), see below. >>> >>>> + >>>> + while (p) { >>>> + *p = '/'; >>>> + basename = p + 1; >>>> + p = strchr(p + 1, '/'); >>>> + if (p) { >>>> + *p = '\0'; >>>> + } >>>> + retval = fdt_path_offset(fdt, dupname); >>> The fdt_path_offset_namelen() function exists *exactly* so that you >>> can look up partial parths without having to mangle your input >>> string. Just set the namelen right, and it will ignore anything to >>> the right of that. >> Function fdt_path_offset_namelen() seems more reasonable. >> >> After we call qemu_fdt_add_path() to add "/cpus/cpu-map/socket0/core0" >> successfully, >> if we want to add another path like "/cpus/cpu-map/socket0/core1" we will >> get the error >> -FDT_ERR_NOTFOUND for each partial path. But actually >> "/cpus/cpu-map/socket0" >> already exists, so by using fdt_path_offset_namelen() with right namelen we >> can avoid >> the error retval for this part. > I don't quite follow what you're saying here. AFAICT your logic was > correct - it just involved a lot of mangling the given path (adding > and removing \0s) which becomes unnecessary with > fdt_path_offset_namelen(). Right. >>>> + if (retval < 0 && retval != -FDT_ERR_NOTFOUND) { >>>> + error_report("%s: Invalid path %s: %s", >>>> + __func__, path, fdt_strerror(retval)); >>> If you're getting an error other than FDT_ERR_NOTFOUND here, chances >>> are it's not an invalid path, but a corrupted fdt blob or something >>> else. >> Right, there can be variable reasons for the fail in addition to the invalid >> path. >> >>>> + exit(1); >>>> + } else if (retval == -FDT_ERR_NOTFOUND) { >>>> + retval = fdt_add_subnode(fdt, parent, basename); >>>> + if (retval < 0) { >>>> + break; >>>> + } >> I found another question here. If path "/cpus/cpu-map/socket0/core0" has >> already >> been added, when we want to add another path "/cpus/cpu-map/socket0/core1" >> and go here with retval = fdt_add_subnode(fdt, parent, "cpus"), then retval >> will >> be -FDT_ERR_EXISTS, but we can't just break the loop in this case. >> >> Am I right of the explanation ? > Not exactly. If you called that fdt_add_subnode() in that case you > would get FDT_ERR_EXISTS. However, because the previous > fdt_path_offset() has returned -FDT_ERR_NOTFOUND, you've already > established that the partial path doesn't exist, so if you got an > FDT_ERR_EXISTS here something has gone very strangely wrong (such as > concurrent access to the flat tree, which would very likely corrupt > it). Thanks for the analysis, I was wrong... > Note that the repeated use of fdt_path_offset() in this function will > repeatedly rescan the whole fdt from the beginning. If you're > concerned about performance (which you might well not be), then a more > efficient approach would be to take your input path component by > component and use fdt_subnode_offset() directly. I will try to address your comments and have some rework for this patch in next version. Thanks, Yanan >
diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h index 8a2fe55622..ef060a9759 100644 --- a/include/sysemu/device_tree.h +++ b/include/sysemu/device_tree.h @@ -121,6 +121,7 @@ uint32_t qemu_fdt_get_phandle(void *fdt, const char *path); uint32_t qemu_fdt_alloc_phandle(void *fdt); int qemu_fdt_nop_node(void *fdt, const char *node_path); int qemu_fdt_add_subnode(void *fdt, const char *name); +int qemu_fdt_add_path(void *fdt, const char *path); #define qemu_fdt_setprop_cells(fdt, node_path, property, ...) \ do { \ diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c index 2691c58cf6..8592c7aa1b 100644 --- a/softmmu/device_tree.c +++ b/softmmu/device_tree.c @@ -541,8 +541,8 @@ int qemu_fdt_add_subnode(void *fdt, const char *name) retval = fdt_add_subnode(fdt, parent, basename); if (retval < 0) { - error_report("FDT: Failed to create subnode %s: %s", name, - fdt_strerror(retval)); + error_report("%s: Failed to create subnode %s: %s", + __func__, name, fdt_strerror(retval)); exit(1); } @@ -550,6 +550,47 @@ int qemu_fdt_add_subnode(void *fdt, const char *name) return retval; } +/* + * Like qemu_fdt_add_subnode(), but will add all missing + * subnodes in the path. + */ +int qemu_fdt_add_path(void *fdt, const char *path) +{ + char *dupname, *basename, *p; + int parent, retval = -1; + + if (path[0] != '/') { + return retval; + } + + parent = fdt_path_offset(fdt, "/"); + p = dupname = g_strdup(path); + + while (p) { + *p = '/'; + basename = p + 1; + p = strchr(p + 1, '/'); + if (p) { + *p = '\0'; + } + retval = fdt_path_offset(fdt, dupname); + if (retval < 0 && retval != -FDT_ERR_NOTFOUND) { + error_report("%s: Invalid path %s: %s", + __func__, path, fdt_strerror(retval)); + exit(1); + } else if (retval == -FDT_ERR_NOTFOUND) { + retval = fdt_add_subnode(fdt, parent, basename); + if (retval < 0) { + break; + } + } + parent = retval; + } + + g_free(dupname); + return retval; +} + void qemu_fdt_dumpdtb(void *fdt, int size) { const char *dumpdtb = current_machine->dumpdtb;