On Thu, Dec 5, 2024 at 11:34 PM Daniel Henrique Barboza
<dbarb...@ventanamicro.com> wrote:
>
> From: Tomasz Jeznach <tjezn...@rivosinc.com>
>
> Now that we have every piece in place we can advertise CAP_HTM to
> software, allowing any HPM aware driver to make use of the counters.
>
> HPM is enabled/disabled via the 'hpm-counters' attribute. Default value
> is 31, max value is also 31. Setting it to zero will disable HPM
> support.
>
> Signed-off-by: Tomasz Jeznach <tjezn...@rivosinc.com>
> Signed-off-by: Daniel Henrique Barboza <dbarb...@ventanamicro.com>
Acked-by: Alistair Francis <alistair.fran...@wdc.com>
Alistair
> ---
> hw/riscv/riscv-iommu.c | 21 +++++++++++++++++++++
> 1 file changed, 21 insertions(+)
>
> diff --git a/hw/riscv/riscv-iommu.c b/hw/riscv/riscv-iommu.c
> index 83cd529844..7df40900b0 100644
> --- a/hw/riscv/riscv-iommu.c
> +++ b/hw/riscv/riscv-iommu.c
> @@ -2256,6 +2256,15 @@ static void riscv_iommu_realize(DeviceState *dev,
> Error **errp)
> RISCV_IOMMU_CAP_SV48X4 | RISCV_IOMMU_CAP_SV57X4;
> }
>
> + if (s->hpm_cntrs > 0) {
> + /* Clip number of HPM counters to maximum supported (31). */
> + if (s->hpm_cntrs > RISCV_IOMMU_IOCOUNT_NUM) {
> + s->hpm_cntrs = RISCV_IOMMU_IOCOUNT_NUM;
> + }
> + /* Enable hardware performance monitor interface */
> + s->cap |= RISCV_IOMMU_CAP_HPM;
> + }
> +
> /* Out-of-reset translation mode: OFF (DMA disabled) BARE (passthrough)
> */
> s->ddtp = set_field(0, RISCV_IOMMU_DDTP_MODE, s->enable_off ?
> RISCV_IOMMU_DDTP_MODE_OFF :
> RISCV_IOMMU_DDTP_MODE_BARE);
> @@ -2303,6 +2312,18 @@ static void riscv_iommu_realize(DeviceState *dev,
> Error **errp)
> RISCV_IOMMU_TR_REQ_CTL_GO_BUSY);
> }
>
> + /* If HPM registers are enabled. */
> + if (s->cap & RISCV_IOMMU_CAP_HPM) {
> + /* +1 for cycle counter bit. */
> + stl_le_p(&s->regs_ro[RISCV_IOMMU_REG_IOCOUNTINH],
> + ~((2 << s->hpm_cntrs) - 1));
> + stq_le_p(&s->regs_ro[RISCV_IOMMU_REG_IOHPMCYCLES], 0);
> + memset(&s->regs_ro[RISCV_IOMMU_REG_IOHPMCTR_BASE],
> + 0x00, s->hpm_cntrs * 8);
> + memset(&s->regs_ro[RISCV_IOMMU_REG_IOHPMEVT_BASE],
> + 0x00, s->hpm_cntrs * 8);
> + }
> +
> /* Memory region for downstream access, if specified. */
> if (s->target_mr) {
> s->target_as = g_new0(AddressSpace, 1);
> --
> 2.47.1
>
>
