On Tue, 2 Jun 2026 16:18:04 -0700 Davidlohr Bueso <[email protected]> wrote:
> Change the default CXL Fixed Memory Window restrictions from 0x2f to > 0xe, dropping Device Coherent and Back-Invalidate. > > host-only coherent combined with Back-Invalidate is undefined behavior. That one I'm fine with. > Device Coherent alongside host-only coherent is permitted by the spec > (multiple restriction bits may be set) but advertises conflicting > coherency modes; neither belongs in the host-only default. Why not in the default? Software should be fine with it and it means the default emulation is slightly more likely to function for simple cases. I don't feel that strongly about it given we don't have an device coherent devices emulated in QEMU, but wanted to understand your reasoning a little more. Jonathan > > Signed-off-by: Davidlohr Bueso <[email protected]> > --- > hw/acpi/cxl.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/hw/acpi/cxl.c b/hw/acpi/cxl.c > index f92f7fa3d558..5ce5e8e083ba 100644 > --- a/hw/acpi/cxl.c > +++ b/hw/acpi/cxl.c > @@ -172,7 +172,7 @@ static void cedt_build_cfmws(CXLFixedWindow *fw, Aml > *cedt) > build_append_int_noprefix(table_data, fw->enc_int_gran, 4); > > /* Window Restrictions */ > - build_append_int_noprefix(table_data, 0x2f, 2); > + build_append_int_noprefix(table_data, 0xe, 2); > > /* QTG ID */ > build_append_int_noprefix(table_data, 0, 2);
