On Mon, Jul 14, 2025 at 06:02:26PM +0100, Jonathan Cameron wrote:
> On Mon, 14 Jul 2025 09:45:31 -0700
> Fan Ni <nifan....@gmail.com> wrote:
>
> > On Mon, Jul 14, 2025 at 03:16:38PM +0100, Jonathan Cameron wrote:
> > > On Mon, 14 Jul 2025 15:15:12 +0100
> > > Jonathan Cameron <jonathan.came...@huawei.com> wrote:
> > >
> > > > On Mon, 14 Jul 2025 15:02:18 +0100
> > > > Jonathan Cameron <jonathan.came...@huawei.com> wrote:
> > > >
> > > > > On Mon, 14 Jul 2025 05:32:19 -0400
> > > > > "Michael S. Tsirkin" <m...@redhat.com> wrote:
> > > > >
> > > > > > On Wed, Jul 02, 2025 at 05:02:13PM +0100, Jonathan Cameron wrote:
> > > > > >
> > > > > > > From: Anisa Su <anisa...@samsung.com>
> > > > > > >
> > > > > > > FM DCD Management command 0x5602 implemented per CXL r3.2 Spec
> > > > > > > Section 7.6.7.6.3
> > > > > > >
> > > > > > > Reviewed-by: Fan Ni <fan...@samsung.com>
> > > > > > > Signed-off-by: Anisa Su <anisa...@samsung.com>
> > > > > > > Signed-off-by: Jonathan Cameron <jonathan.came...@huawei.com>
> > > > > > >
> > > > >
> > > > >
> > > > > > > diff --git a/hw/cxl/cxl-mailbox-utils.c
> > > > > > > b/hw/cxl/cxl-mailbox-utils.c
> > > > > > > index bf1710b251..1fc453f70d 100644
> > > > > > > --- a/hw/cxl/cxl-mailbox-utils.c
> > > > > > > +++ b/hw/cxl/cxl-mailbox-utils.c
> > > > >
> > > > > > > +/* CXL r3.2 section 7.6.7.6.3: Set Host DC Region Configuration
> > > > > > > (Opcode 5602) */
> > > > > > > +static CXLRetCode cmd_fm_set_dc_region_config(const struct
> > > > > > > cxl_cmd *cmd,
> > > > > > > + uint8_t
> > > > > > > *payload_in,
> > > > > > > + size_t len_in,
> > > > > > > + uint8_t
> > > > > > > *payload_out,
> > > > > > > + size_t *len_out,
> > > > > > > + CXLCCI *cci)
> > > > > > > +{
> > > > > > > + struct {
> > > > > > > + uint8_t reg_id;
> > > > > > > + uint8_t rsvd[3];
> > > > > > > + uint64_t block_sz;
> > > > > > > + uint8_t flags;
> > > > > > > + uint8_t rsvd2[3];
> > > > > > > + } QEMU_PACKED *in = (void *)payload_in;
> > > > > > > + CXLType3Dev *ct3d = CXL_TYPE3(cci->d);
> > > > > > > + CXLEventDynamicCapacity dcEvent = {};
> > > > > > > + CXLDCRegion *region = &ct3d->dc.regions[in->reg_id];
> > > > > > > +
> > > > > > > + /*
> > > > > > > + * CXL r3.2 7.6.7.6.3: Set DC Region Configuration
> > > > > > > + * This command shall fail with Unsupported when the
> > > > > > > Sanitize on Release
> > > > > > > + * field does not match the region’s configuration... and
> > > > > > > the device
> > > > > > > + * does not support reconfiguration of the Sanitize on
> > > > > > > Release setting.
> > > > > > > + *
> > > > > > > + * Currently not reconfigurable, so always fail if sanitize
> > > > > > > bit (bit 0)
> > > > > > > + * doesn't match.
> > > > > > > + */
> > > > > > > + if ((in->flags & 0x1) != (region->flags & 0x1)) {
> > > > > > > + return CXL_MBOX_UNSUPPORTED;
> > > > > > > + }
> > > > > > > +
> > > > > > > + if (in->reg_id >= DCD_MAX_NUM_REGION) {
> > > > > > > + return CXL_MBOX_UNSUPPORTED;
> > > > > > > + }
> > > > > > > +
> > > > > > > + /* Check that no extents are in the region being
> > > > > > > reconfigured */
> > > > > > > + if (!bitmap_empty(region->blk_bitmap, region->len /
> > > > > > > region->block_size)) {
> > > > > > > + return CXL_MBOX_UNSUPPORTED;
> > > > > > > + }
> > > > > > > +
> > > > > > > + /* Check that new block size is supported */
> > > > > > > + if (!test_bit(BIT((int) log2(in->block_sz)),
> > > > > > > + ®ion->supported_blk_size_bitmask)) {
> > > > > > > + return CXL_MBOX_INVALID_INPUT;
> > > > > > > + }
> > > > > >
> > > > > > This does not work: test_bit works on unsigned long, while
> > > > > > supported_blk_size_bitmask is uint64_t.
> > > > > >
> > > > > > Why so funky? what is wrong with:
> > > > > >
> > > > > > if (!(BIT_ULL(log2(in->block_sz)) &
> > > > > > region->supported_blk_size_bitmask))
> > > > > >
> > > > > > And BTW why cast to int here?
> > > > This became obvious when your suggestion didn't build :(
> > > >
> > > > ./../hw/cxl/cxl-mailbox-utils.c: In function
> > > > ‘cmd_fm_set_dc_region_config’:
> > > > /home/jic23/src/qemu/include/qemu/bitops.h:25:39: error: invalid
> > > > operands to binary << (have ‘long long unsigned int’ and ‘double’)
> > > > 25 | #define BIT_ULL(nr) (1ULL << (nr))
> > > > | ^~ ~~~~
> > > > ../../hw/cxl/cxl-mailbox-utils.c:3436:11: note: in expansion of macro
> > > > ‘BIT_ULL’
> > > > 3436 | if (!(BIT_ULL(log2(in->block_sz)) &
> > > > region->supported_blk_size_bitmask)) {
> > > > | ^~~~~~~
> > > >
> > > > Now I look again, this is effectively 2**(log_2(x)) or x. So
> > > > if (in->block_sz & region->supporte_blk_size_bitmask)
> > >
> > > it (!(in->block_sz & region->supports_blk_size_bitmask))
> > >
> > > I mean.
> >
> > Make sense to me.
> >
> > The only thing is how to detect the violation if the passed in block_sz
> > is not power of 2.
> > Or who will do the check if not in qemu?
> Hi Fan,
>
> I checked the spec on this. There isn't an explicit statement that the device
> should return an error on this. Looks to be impdef. I'd happily see such
> a check as a usability improvement though!
>
> I'm just not set up to test this right now so decided to be
> risk averse and not trying adding one.
>
> If you want to send a patch on top I'd be happy to add it.
>
> Jonathan
>
>
Would something like this work?
/* Check that new block size is supported */
if (!is_power_of_2(in->block_sz) ||
!(in->block_sz & region->supported_blk_size_bitmask)) {
return CXL_MBOX_INVALID_INPUT;
}
I did not have to add any extra headers to use this helper function in
include/qemu/host-utils.h and it compiles for me.
Anisa
>
> >
> > Fan
> >
> > >
> > >
> > > > Should work as long as we know block_size is a power of 2 (which the
> > > > specification
> > > > says it must be).
> > > >
> > > > Anisa?
> > > >
> > > > >
> > > > > Change looks fine to me, so I'll prepare an updated set with this
> > > > > and the missing semi colon. Anisa if you can have a look at this
> > > > > that would be great.
> > > > >
> > > > > Sorry I seem to have missed Anisa off the cc for this!
> > > > >
> > > > > Jonathan
> > > > >
> > > >
> > >
> >
>
