performance: 0.889 device: 0.856 graphic: 0.799 network: 0.740 semantic: 0.601 socket: 0.553 permissions: 0.531 debug: 0.483 boot: 0.446 vnc: 0.428 PID: 0.356 KVM: 0.310 other: 0.308 files: 0.183 intel-hda: SD_STS different behavior for byte write vs. word write Description of problem: The Intel HDA SD_STS register is accessible two different ways in QEMU: either it's the top 8 bits of a 32-bit access or it's directly accessible as a byte. On reads, the register behavior for SD_STS is identical whether accessed as a 32-bit read or an 8-bit read. On writes, the behavior is different; when written to as an 8-bit write, the BCIS, FIFOE, and DESE bits implement the documented HDA behavior of RW1C (writing a 1 to a bit clears it). When written to as the top 8 bits of a 32-bit write, writing a 1 to a bit sets the bit -- so an attempt to clear a status bit instead unconditionally sets the status bit. Steps to reproduce: 1. Write 32 bits at SD_CTL address with bit 27 set (FIFOE). This should clear FIFOE, but does not. 2. Read back SD_STS (SD_CTL address + 3) as a byte. The FIFOE bit will be set. 3. Write 8 bits at SD_STS address with bit 3 set (FIFOE). This should clear FIFOE, and it does. 4. Read back SD_STS as a byte. The FIFOE bit will be cleared. Additional information: