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

[Daniel Henrique Barboza <dbarboza@ventanamicro.com>]

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(-)
>