Current FIFO handling code does not reset RXFE/RXFF flags when guest
resets FIFO by writing to UARTLCR register, although internal FIFO state
is reset to 0 read count. Actual guest-visible flag update will happen
only on next data read or write attempt. As a result of that any guest
that expects RXFE flag to be set (and RXFF to be cleared) after resetting
FIFO will never see that happen.
Signed-off-by: Evgeny Iakovlev <eiakovlev@linux.microsoft.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20230123162304.26254-5-eiakovlev@linux.microsoft.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Previous change slightly modified the way we handle data writes when
FIFO is disabled. Previously we kept incrementing read_pos and were
storing data at that position, although we only have a
single-register-deep FIFO now. Then we changed it to always store data
at pos 0.
If guest disables FIFO and the proceeds to read data, it will work out
fine, because we still read from current read_pos before setting it to
0.
However, to make code less fragile, introduce a post_load hook for
PL011State and move fixup read FIFO state when FIFO is disabled. Since
we are introducing a post_load hook, also do some sanity checking on
untrusted incoming input state.
Signed-off-by: Evgeny Iakovlev <eiakovlev@linux.microsoft.com>
Message-id: 20230123162304.26254-3-eiakovlev@linux.microsoft.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
PL011 can be in either of 2 modes depending guest config: FIFO and
single register. The last mode could be viewed as a 1-element-deep FIFO.
Current code open-codes a bunch of depth-dependent logic. Refactor FIFO
depth handling code to isolate calculating current FIFO depth.
One functional (albeit guest-invisible) side-effect of this change is
that previously we would always increment s->read_pos in UARTDR read
handler even if FIFO was disabled, now we are limiting read_pos to not
exceed FIFO depth (read_pos itself is reset to 0 if user disables FIFO).
Signed-off-by: Evgeny Iakovlev <eiakovlev@linux.microsoft.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20230123162304.26254-2-eiakovlev@linux.microsoft.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Qemu doesn't implement Debug Communication Channel, as well as the rest
of external debug interface. However, Microsoft Hyper-V in tries to
access some of those registers during an EL2 context switch.
Since there is no architectural way to not advertise support for external
debug, provide RAZ/WI stubs for OSDTRRX_EL1, OSDTRTX_EL1 and OSECCR_EL1
registers in the same way the rest of DCM is currently done. Do account
for access traps though with access_tda.
Signed-off-by: Evgeny Iakovlev <eiakovlev@linux.microsoft.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20230120155929.32384-3-eiakovlev@linux.microsoft.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
ARM trusted firmware, when built with FEAT_HCX support, sets SCR_EL3.HXEn bit
to allow EL2 to modify HCRX_EL2 register without trapping it in EL3. Qemu
uses a valid mask to clear unsupported SCR_EL3 bits when emulating SCR_EL3
write, and that mask doesn't include SCR_EL3.HXEn bit even if FEAT_HCX is
enabled and exposed to the guest. As a result EL3 writes of that bit are
ignored.
Cc: qemu-stable@nongnu.org
Signed-off-by: Evgeny Iakovlev <eiakovlev@linux.microsoft.com>
Message-id: 20230105221251.17896-4-eiakovlev@linux.microsoft.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Evgeny Iakovlev