| Message ID | 20210909163441.44418-4-kevin.stefanov@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Fix alignment of FACS in guests | expand |
On 09.09.2021 18:34, Kevin Stefanov wrote: > RSDP's size is 64 bytes and later in the function, its buffer is > hardcoded to be 64 bytes long. Don't bother to allocate a whole page. > > Signed-off-by: Kevin Stefanov <kevin.stefanov@citrix.com> Purely technically and within the constraints of the present code: Reviewed-by: Jan Beulich <jbeulich@suse.com> However, ... > --- a/tools/libs/light/libxl_x86_acpi.c > +++ b/tools/libs/light/libxl_x86_acpi.c > @@ -183,7 +183,7 @@ int libxl__dom_load_acpi(libxl__gc *gc, > goto out; > } > > - config.rsdp = (unsigned long)libxl__malloc(gc, libxl_ctxt.page_size); > + config.rsdp = (unsigned long)libxl__malloc(gc, 64); ... this is the 4th literal 64 in the function (including one in a comment), all of which are meant to represent the same abstract thing. And none of which look to be really correct: sizeof(struct acpi_20_rsdp) == 36 according to my counting. While I don't mind using 64 (for the time being), I think this should then be via a #define, which would be accompanied by a respective comment. Or else via sizeof(struct acpi_20_rsdp). But of course hard-coding the size isn't really forward compatible anyway. It should rather be libacpi to specify what size the blob is. And then it might be safer to stick to allocating a full page here, as the actual size won't be known up front. Or the allocated size would need to become an input to acpi_build_tables(), so that it wouldn't risk overrunning the space. Jan
diff --git a/tools/libs/light/libxl_x86_acpi.c b/tools/libs/light/libxl_x86_acpi.c index 0a82e7cacd..2aea1eca31 100644 --- a/tools/libs/light/libxl_x86_acpi.c +++ b/tools/libs/light/libxl_x86_acpi.c @@ -183,7 +183,7 @@ int libxl__dom_load_acpi(libxl__gc *gc, goto out; } - config.rsdp = (unsigned long)libxl__malloc(gc, libxl_ctxt.page_size); + config.rsdp = (unsigned long)libxl__malloc(gc, 64); config.infop = (unsigned long)libxl__malloc(gc, libxl_ctxt.page_size); /* Pages to hold ACPI tables */ acpi_pages = libxl__malloc(gc, (NUM_ACPI_PAGES + 1) *
RSDP's size is 64 bytes and later in the function, its buffer is hardcoded to be 64 bytes long. Don't bother to allocate a whole page. Signed-off-by: Kevin Stefanov <kevin.stefanov@citrix.com> --- CC: Andrew Cooper <andrew.cooper3@citrix.com> CC: Ian Jackson <iwj@xenproject.org> CC: Wei Liu <wl@xen.org> CC: Anthony PERARD <anthony.perard@citrix.com> --- tools/libs/light/libxl_x86_acpi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)