Re: [PATCH v2 0/6] target/riscv: Add RISC-V Virtual IRQs and IRQ filtering support

[Rajnesh Kanwal]

Hey Daniel,

Sorry I was on holiday. There is no new work on this AFAIK. I will
rebase and send a new version for this shortly.

Thanks
Rajnesh

On Wed, Sep 6, 2023 at 3:38 PM Daniel Henrique Barboza
<dbarboza@ventanamicro.com> wrote:
>
> Hey,
>
>
> What's the latest on this work? It seems that all patches are acked:
>
> https://lore.kernel.org/qemu-riscv/20230526162308.22892-1-rkanwal@rivosinc.com/
>
>
> It'll probably conflict with current Alistair's riscv-to-apply.next though, so
> perhaps Rajnesh could gather the acks and send a rebased version.
>
>
> Thanks,
>
> Daniel
>
>
> On 5/26/23 13:23, Rajnesh Kanwal wrote:
> > This series adds M and HS-mode virtual interrupt and IRQ filtering support.
> > This allows inserting virtual interrupts from M/HS-mode into S/VS-mode
> > using mvien/hvien and mvip/hvip csrs. IRQ filtering is a use case of
> > this change, i-e M-mode can stop delegating an interrupt to S-mode and
> > instead enable it in MIE and receive those interrupts in M-mode and then
> > selectively inject the interrupt using mvien and mvip.
> >
> > Also, the spec doesn't mandate the interrupt to be actually supported
> > in hardware. Which allows M/HS-mode to assert virtual interrupts to
> > S/VS-mode that have no connection to any real interrupt events.
> >
> > This is defined as part of the AIA specification [0], "5.3 Interrupt
> > filtering and virtual interrupts for supervisor level" and "6.3.2 Virtual
> > interrupts for VS level".
> >
> > Most of the testing is done by hacking around OpenSBI and linux host.
> > The changes for those can be found at [1] and [2].
> >
> > It's my first touch on RISC-V qemu IRQ subsystem. Any feedback would
> > be much appreciated.
> >
> > The change can also be found on github [3].
> >
> > TODO: This change doesn't support delegating virtual interrupts injected
> > by M-mode to VS-mode by the Hypervisor. This is true for bits 13:63 only.
> >
> > Thanks
> > Rajnesh
> >
> > [0]: 
> > https://github.com/riscv/riscv-aia/releases/download/1.0-RC4/riscv-interrupts-1.0-RC4.pdf
> > [1]: https://github.com/rajnesh-kanwal/opensbi/tree/dev/rkanwal/irq_filter
> > [2]: 
> > https://github.com/rajnesh-kanwal/linux/commits/dev/rkanwal/aia_irq_filter
> > [3]: 
> > https://github.com/rajnesh-kanwal/qemu/tree/dev/rkanwal/riscv_irq_filter
> >
> > v2:
> >   * Move RISCV_EXCP_SEMIHOST to switch case and remove special handling.
> >   * Fix linux-user build.
> >
> > Rajnesh Kanwal (6):
> >    target/riscv: Without H-mode mask all HS mode inturrupts in mie.
> >    target/riscv: Check for async flag in case of RISCV_EXCP_SEMIHOST.
> >    target/riscv: Set VS* bits to one in mideleg when H-Ext is enabled
> >    target/riscv: Split interrupt logic from riscv_cpu_update_mip.
> >    target/riscv: Add M-mode virtual interrupt and IRQ filtering support.
> >    target/riscv: Add HS-mode virtual interrupt and IRQ filtering support.
> >
> >   target/riscv/cpu.c        |   9 +-
> >   target/riscv/cpu.h        |  23 ++
> >   target/riscv/cpu_bits.h   |   6 +
> >   target/riscv/cpu_helper.c |  99 +++++---
> >   target/riscv/csr.c        | 477 ++++++++++++++++++++++++++++++++++----
> >   target/riscv/machine.c    |   6 +
> >   6 files changed, 546 insertions(+), 74 deletions(-)
> >