Re: [PATCH v4] powernv: boot OpenBSD on POWER9

[Chinmay Rath <rathc@linux.ibm.com>]

On 7/19/26 20:25, Kirill A. Korinsky wrote:
> The POWER9 Processor User's Manual, section 4.9.4, specifies that POWER9
> ignores PTCR[PATS] and only supports a 64 KiB partition table. Use an
> effective PATS value of 4 on POWER9; other processors keep the existing
> ISA v3.0 interpretation.
>
> The PSI model now exposes POWER9 IRQ level and pending status registers,
> and keeps both updated while delivering through the existing XIVE LSI
> source. This lets guests that select the POWER9 PSI LSI IRQ method
> continue to receive LPC interrupts.
>
> The blast radius is probably minimal: the PTCR change is limited to
> POWER9, while the PSI change only touches POWER9 PSI state and reuses
> the existing delivery path.
> ---
>   hw/ppc/pnv_psi.c                       | 11 ++++--
>   target/ppc/mmu-book3s-v3.c             | 21 +++++++++--
Acked-by: Chinmay Rath <rathc@linux.ibm.com>
>   tests/functional/ppc64/meson.build     |  2 +
>   tests/functional/ppc64/test_openbsd.py | 52 ++++++++++++++++++++++++++
>   4 files changed, 79 insertions(+), 7 deletions(-)
>   create mode 100755 tests/functional/ppc64/test_openbsd.py
>
> diff --git a/hw/ppc/pnv_psi.c b/hw/ppc/pnv_psi.c
> index e8701c6100..39ec448f3c 100644
> --- a/hw/ppc/pnv_psi.c
> +++ b/hw/ppc/pnv_psi.c
> @@ -688,6 +688,8 @@ static uint64_t pnv_psi_p9_mmio_read(void *opaque, hwaddr addr, unsigned size)
>       case PSIHB9_ESB_CI_BASE:
>       case PSIHB9_ESB_NOTIF_ADDR:
>       case PSIHB9_IVT_OFFSET:
> +    case PSIHB9_IRQ_LEVEL:
> +    case PSIHB9_IRQ_STAT:
>           val = psi->regs[reg];
>           break;
>       default:
> @@ -818,17 +820,20 @@ static void pnv_psi_power9_set_irq(void *opaque, int irq, int state)
>   {
>       PnvPsi *psi = opaque;
>       uint64_t irq_method = psi->regs[PSIHB_REG(PSIHB9_INTERRUPT_CONTROL)];
> +    uint64_t irq_bit = PPC_BIT(irq);
>   
>       if (irq_method & PSIHB9_IRQ_METHOD) {
>           qemu_log_mask(LOG_GUEST_ERROR, "PSI: LSI IRQ method no supported\n");
>           return;
>       }
>   
> -    /* Update LSI levels */
> +    /* Update LSI levels and pending status */
>       if (state) {
> -        psi->regs[PSIHB_REG(PSIHB9_IRQ_LEVEL)] |= PPC_BIT(irq);
> +        psi->regs[PSIHB_REG(PSIHB9_IRQ_LEVEL)] |= irq_bit;
> +        psi->regs[PSIHB_REG(PSIHB9_IRQ_STAT)] |= irq_bit;
>       } else {
> -        psi->regs[PSIHB_REG(PSIHB9_IRQ_LEVEL)] &= ~PPC_BIT(irq);
> +        psi->regs[PSIHB_REG(PSIHB9_IRQ_LEVEL)] &= ~irq_bit;
> +        psi->regs[PSIHB_REG(PSIHB9_IRQ_STAT)] &= ~irq_bit;
>       }
>   
>       qemu_set_irq(psi->qirqs[irq], state);
> diff --git a/target/ppc/mmu-book3s-v3.c b/target/ppc/mmu-book3s-v3.c
> index 3865556310..f329a7a0f2 100644
> --- a/target/ppc/mmu-book3s-v3.c
> +++ b/target/ppc/mmu-book3s-v3.c
> @@ -23,24 +23,37 @@
>   #include "mmu-hash64.h"
>   #include "mmu-book3s-v3.h"
>   
> +#define PPC64_V3_PATE_SIZE 16 /* two 64-bit words */
> +
>   bool ppc64_v3_get_pate(PowerPCCPU *cpu, target_ulong lpid, ppc_v3_pate_t *entry)
>   {
>       uint64_t patb = cpu->env.spr[SPR_PTCR] & PTCR_PATB;
>       uint64_t pats = cpu->env.spr[SPR_PTCR] & PTCR_PATS;
> +    uint64_t table_size;
> +    uint64_t entries;
> +
> +    /*
> +     * The POWER9 Processor User's Manual, section 4.9.4, specifies that
> +     * POWER9 ignores PTCR[PATS] and only supports a 64 KiB partition table.
> +     */
> +    if (cpu->env.excp_model == POWERPC_EXCP_POWER9) {
> +        pats = 4;
> +    }
> +    table_size = 1ULL << (pats + 12);
>   
>       /* Check if partition table is properly aligned */
> -    if (patb & MAKE_64BIT_MASK(0, pats + 12)) {
> +    if (patb & (table_size - 1)) {
>           return false;
>       }
>   
>       /* Calculate number of entries */
> -    pats = 1ull << (pats + 12 - 4);
> -    if (pats <= lpid) {
> +    entries = table_size / PPC64_V3_PATE_SIZE;
> +    if (entries <= lpid) {
>           return false;
>       }
>   
>       /* Grab entry */
> -    patb += 16 * lpid;
> +    patb += PPC64_V3_PATE_SIZE * lpid;
>       entry->dw0 = ldq_phys(CPU(cpu)->as, patb);
>       entry->dw1 = ldq_phys(CPU(cpu)->as, patb + 8);
>       return true;
> diff --git a/tests/functional/ppc64/meson.build b/tests/functional/ppc64/meson.build
> index f0f8ab8f61..cb3c745624 100644
> --- a/tests/functional/ppc64/meson.build
> +++ b/tests/functional/ppc64/meson.build
> @@ -4,6 +4,7 @@ test_ppc64_timeouts = {
>     'fadump' : 480,
>     'hv' : 1000,
>     'mac99' : 120,
> +  'openbsd' : 240,
>     'powernv' : 480,
>     'pseries' : 480,
>     'replay' : 210,
> @@ -20,6 +21,7 @@ tests_ppc64_system_thorough = [
>     'fadump',
>     'hv',
>     'mac99',
> +  'openbsd',
>     'powernv',
>     'pseries',
>     'replay',
> diff --git a/tests/functional/ppc64/test_openbsd.py b/tests/functional/ppc64/test_openbsd.py
> new file mode 100755
> index 0000000000..bdbef6bf82
> --- /dev/null
> +++ b/tests/functional/ppc64/test_openbsd.py
> @@ -0,0 +1,52 @@
> +#!/usr/bin/env python3
> +#
> +# Test that OpenBSD boots on a ppc powernv machine and reaches the installer.
> +#
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +
> +from qemu_test import QemuSystemTest, Asset
> +from qemu_test import wait_for_console_pattern
> +
> +
> +class OpenBSDPowerNV(QemuSystemTest):
> +
> +    ASSET_MINIROOT = Asset(
> +        'https://kirill.korins.ky/pub/qemu-powerpc64-openbsd/miniroot79.img',
> +        '7829e42b75d81cafd732038b9d63228b79c1f5828d8375872a4bb655e1d6b13c')
> +
> +    ASSET_BOOTKERNEL = Asset(
> +        'https://kirill.korins.ky/pub/qemu-powerpc64-openbsd/pnor.BOOTKERNEL',
> +        '397ce43ce61910e1a2c4f13d301f957e61513a9ec5371bc3e87d3095411fae7b')
> +
> +    def test_powernv9_openbsd_installer(self):
> +        self.set_machine('powernv9')
> +        self.require_accelerator('tcg')
> +
> +        miniroot_path = self.ASSET_MINIROOT.fetch()
> +        bootkernel_path = self.ASSET_BOOTKERNEL.fetch()
> +
> +        self.vm.set_console()
> +        self.vm.add_args('-cpu', 'power9',
> +                         '-accel', 'tcg,thread=single',
> +                         '-smp', '1,cores=1,threads=1',
> +                         '-m', '2g',
> +                         '-kernel', bootkernel_path,
> +                         '-device',
> +                         'ich9-ahci,id=sata0,bus=pcie.0,addr=0x0',
> +                         '-drive',
> +                         f'file={miniroot_path},format=raw,if=none,'
> +                         'id=bootdisk,snapshot=on',
> +                         '-device',
> +                         'ide-hd,bus=sata0.0,unit=0,drive=bootdisk,'
> +                         'bootindex=1')
> +        self.vm.launch()
> +
> +        wait_for_console_pattern(self, 'OpenBSD 7.9 (RAMDISK)', 'panic:')
> +        wait_for_console_pattern(
> +            self,
> +            '(I)nstall, (U)pgrade, (A)utoinstall or (S)hell?',
> +            'panic:')
> +
> +
> +if __name__ == '__main__':
> +    QemuSystemTest.main()