On Mon, 2024-02-26 at 15:32 +0100, Juergen Gross wrote: > On 26.02.24 09:25, isaku.yamahata@xxxxxxxxx wrote: > > From: Kai Huang <kai.huang@xxxxxxxxx> > > > > For now the kernel only reads TDMR related global metadata fields for > > module initialization. All these fields are 16-bits, and the kernel > > only supports reading 16-bits fields. > > > > KVM will need to read a bunch of non-TDMR related metadata to create and > > run TDX guests. It's essential to provide a generic metadata read > > infrastructure which supports reading all 8/16/32/64 bits element sizes. > > > > Extend the metadata read to support reading all these element sizes. > > > > Signed-off-by: Kai Huang <kai.huang@xxxxxxxxx> > > Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx> > > --- > > arch/x86/virt/vmx/tdx/tdx.c | 59 +++++++++++++++++++++++++------------ > > arch/x86/virt/vmx/tdx/tdx.h | 2 -- > > 2 files changed, 40 insertions(+), 21 deletions(-) > > > > diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c > > index eb208da4ff63..a19adc898df6 100644 > > --- a/arch/x86/virt/vmx/tdx/tdx.c > > +++ b/arch/x86/virt/vmx/tdx/tdx.c > > @@ -271,23 +271,35 @@ static int read_sys_metadata_field(u64 field_id, u64 *data) > > return 0; > > } > > > > -static int read_sys_metadata_field16(u64 field_id, > > - int offset, > > - void *stbuf) > > +/* Return the metadata field element size in bytes */ > > +static int get_metadata_field_bytes(u64 field_id) > > { > > - u16 *st_member = stbuf + offset; > > + /* > > + * TDX supports 8/16/32/64 bits metadata field element sizes. > > + * TDX module determines the metadata element size based on the > > + * "element size code" encoded in the field ID (see the comment > > + * of MD_FIELD_ID_ELE_SIZE_CODE macro for specific encodings). > > + */ > > + return 1 << MD_FIELD_ID_ELE_SIZE_CODE(field_id); > > +} > > + > > +static int stbuf_read_sys_metadata_field(u64 field_id, > > + int offset, > > + int bytes, > > + void *stbuf) > > +{ > > + void *st_member = stbuf + offset; > > u64 tmp; > > int ret; > > > > - if (WARN_ON_ONCE(MD_FIELD_ID_ELE_SIZE_CODE(field_id) != > > - MD_FIELD_ID_ELE_SIZE_16BIT)) > > + if (WARN_ON_ONCE(get_metadata_field_bytes(field_id) != bytes)) > > return -EINVAL; > > > > ret = read_sys_metadata_field(field_id, &tmp); > > if (ret) > > return ret; > > > > - *st_member = tmp; > > + memcpy(st_member, &tmp, bytes); > > > > return 0; > > } > > @@ -295,11 +307,30 @@ static int read_sys_metadata_field16(u64 field_id, > > struct field_mapping { > > u64 field_id; > > int offset; > > + int size; > > }; > > > > #define TD_SYSINFO_MAP(_field_id, _struct, _member) \ > > { .field_id = MD_FIELD_ID_##_field_id, \ > > - .offset = offsetof(_struct, _member) } > > + .offset = offsetof(_struct, _member), \ > > + .size = sizeof(typeof(((_struct *)0)->_member)) } > > + > > +static int read_sys_metadata(struct field_mapping *fields, int nr_fields, > > The first parameter should be "const struct field_mapping *fields". > > Indeed. :-)