Fix read value of CSR mip.

[NewPaulWalker]

The read value of mip should not depend on the value of hvip.

hvip.VSSIP is an alias of mip.VSSIP, so when reading hvip, the VSSIP bit of mip needs to be OR-ed. Similarly, when writing to hvip, the VSSIP bit of mip also needs to be updated.

However, there is no reason for the value of mip to depend on the value of hvip when being read.

[demin-han]

#1590 add the hvip read.

[NewPaulWalker]

#1590 add the hvip read.

Yes, the read value of hvip should depend on the value of mip, but the read value of mip should not depend on the value of hvip.

[demin-han]

#1590 add the hvip read.

Yes, the read value of hvip should depend on the value of mip, but the read value of mip should not depend on the value of hvip.

without hvip read, the MIP_VSEIP and MIP_VSTIP will miss when reading mip.
These two bits are stored in hvip.

bool hvip_csr_t::unlogged_write(const reg_t val) noexcept {
state->mip->write_with_mask(MIP_VSSIP, val); // hvip.VSSIP is an alias of mip.VSSIP
const reg_t lscof_int = proc->extension_enabled(EXT_SSCOFPMF) ? MIP_LCOFIP : 0;
return basic_csr_t::unlogged_write(val & (lscof_int | MIP_VSEIP | MIP_VSTIP));
}

[NewPaulWalker]

without hvip read, the MIP_VSEIP and MIP_VSTIP will miss when reading mip.
These two bits are stored in hvip.

Thank you for the reminder!

Yes, the read value of mip should depend on hvip, but only on the hvip.VSEIP and hvip.VSTIP bits.

Previously, directly OR-ing the read value of mip with the read value of hvip was fine. However, after I modified the write behavior of hvip: #1862 — specifically, after implementing the Sscofpmf extension, hvip.LCOFIP became writable. This caused an issue where the entire value of hvip was OR-ed when reading mip.

I will revise the mip read logic to make it depend only on the hvip.VSEIP and hvip.VSTIP bits.
Thank you again for the reminder.