On Fri, Mar 19, 2021 at 04:53:59PM +0000, Alexandru Elisei wrote:
> Currently, the UART early address is set indirectly with the --vmm option
> and there are only two possible values: if the VMM is qemu (the default),
> then the UART address is set to 0x09000000; if the VMM is kvmtool, then the
> UART address is set to 0x3f8.
>
> The upstream kvmtool commit 45b4968e0de1 ("hw/serial: ARM/arm64: Use MMIO
> at higher addresses") changed the UART address to 0x1000000, and
> kvm-unit-tests so far hasn't had mechanism to let the user set a specific
> address, which means that for recent versions of kvmtool the early UART
> won't be available.
>
> This situation will only become worse as kvm-unit-tests gains support to
> run as an EFI app, as each platform will have their own UART type and
> address.
>
> To address both issues, a new configure option is added, --earlycon. The
> syntax and semantics are identical to the kernel parameter with the same
> name. For example, for kvmtool, --earlycon=uart,mmio,0x1000000 will set the
> correct UART address. Specifying this option will overwrite the UART
> address set by --vmm.
>
> At the moment, the UART type and register width parameters are ignored
> since both qemu's and kvmtool's UART emulation use the same offset for the
> TX register and no other registers are used by kvm-unit-tests, but the
> parameters will become relevant once EFI support is added.
>
> Signed-off-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
> ---
> Besides working with current versions of kvmtool, this will also make early
> console work if the user specifies a custom memory layout [1] (patches are
> old, but I plan to pick them up at some point in the future).
>
> Changes in v3:
> * Switched to using IFS and read instead of cut.
> * Fixed typo in option description.
> * Added check that $addr is a valid number.
>
> Changes in v2:
> * kvmtool patches were merged, so I reworked the commit message to point to
> the corresponding kvmtool commit.
> * Restricted pl011 register size to 32 bits, as per Arm Base System
> Architecture 1.0 (DEN0094A), and to match Linux.
> * Reworked the way the fields are extracted to make it more precise
> (without the -s argument, the entire string is echo'ed when no delimiter
> is found).
> * The changes are not trivial, so I dropped Drew's Reviewed-by.
>
> [1] https://lore.kernel.org/kvm/1569245722-23375-1-git-send-email-alexandru.elisei@xxxxxxx/
>
> configure | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 53 insertions(+)
>
Applied to arm/queue
https://gitlab.com/rhdrjones/kvm-unit-tests/-/commits/arm/queue
Thanks,
drew
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