> This is the really low level of guest entry/exit code.
>
> Book3s_64 has an SLB, which stores all ESID -> VSID mappings we're
> currently aware of.
>
> The segments in the guest differ from the ones on the host, so we need
> to switch the SLB to tell the MMU that we're in a new context.
>
> So we store a shadow of the guest's SLB in the PACA, switch to that on
> entry and only restore bolted entries on exit, leaving the rest to the
> Linux SLB fault handler.
>
> That way we get a really clean way of switching the SLB.
>
> Signed-off-by: Alexander Graf
> ---
> arch/powerpc/kvm/book3s_64_slb.S | 277
++
> 1 files changed, 277 insertions(+), 0 deletions(-)
> create mode 100644 arch/powerpc/kvm/book3s_64_slb.S
>
> diff --git a/arch/powerpc/kvm/book3s_64_slb.S b/arch/powerpc/kvm/book3s_64_sl
b.S
> new file mode 100644
> index 000..00a8367
> --- /dev/null
> +++ b/arch/powerpc/kvm/book3s_64_slb.S
> @@ -0,0 +1,277 @@
> +/*
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License, version 2, as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
> + *
> + * Copyright SUSE Linux Products GmbH 2009
> + *
> + * Authors: Alexander Graf
> + */
> +
> +/***
***
> + *
*
> + * Entry code
*
> + *
*
> + ***
**/
> +
> +.global kvmppc_handler_trampoline_enter
> +kvmppc_handler_trampoline_enter:
> +
> + /* Required state:
> + *
> + * MSR = ~IR|DR
> + * R13 = PACA
> + * R9 = guest IP
> + * R10 = guest MSR
> + * R11 = free
> + * R12 = free
> + * PACA[PACA_EXMC + EX_R9] = guest R9
> + * PACA[PACA_EXMC + EX_R10] = guest R10
> + * PACA[PACA_EXMC + EX_R11] = guest R11
> + * PACA[PACA_EXMC + EX_R12] = guest R12
> + * PACA[PACA_EXMC + EX_R13] = guest R13
> + * PACA[PACA_EXMC + EX_CCR] = guest CR
> + * PACA[PACA_EXMC + EX_R3] = guest XER
> + */
> +
> + mtsrr0 r9
> + mtsrr1 r10
> +
> + mtspr SPRN_SPRG_SCRATCH0, r0
> +
> + /* Remove LPAR shadow entries */
> +
> +#if SLB_NUM_BOLTED == 3
You could alternatively check the persistent entry in the slb_shawdow
buffer. This would give you a run time check. Not sure what's best
though.
> +
> + ld r12, PACA_SLBSHADOWPTR(r13)
> + ld r10, 0x10(r12)
> + ld r11, 0x18(r12)
Can you define something in asm-offsets.c for these magic constants 0x10
and 0x18. Similarly below.
> + /* Invalid? Skip. */
> + rldicl. r0, r10, 37, 63
> + beq slb_entry_skip_1
> + xoris r9, r10, slb_esi...@h
> + std r9, 0x10(r12)
> +slb_entry_skip_1:
> + ld r9, 0x20(r12)
> + /* Invalid? Skip. */
> + rldicl. r0, r9, 37, 63
> + beq slb_entry_skip_2
> + xoris r9, r9, slb_esi...@h
> + std r9, 0x20(r12)
> +slb_entry_skip_2:
> + ld r9, 0x30(r12)
> + /* Invalid? Skip. */
> + rldicl. r0, r9, 37, 63
> + beq slb_entry_skip_3
> + xoris r9, r9, slb_esi...@h
> + std r9, 0x30(r12)
Can these 3 be made into a macro?
> +slb_entry_skip_3:
> +
> +#else
> +#error unknown number of bolted entries
> +#endif
> +
> + /* Flush SLB */
> +
> + slbia
> +
> + /* r0 = esid & ESID_MASK */
> + rldicr r10, r10, 0, 35
> + /* r0 |= CLASS_BIT(VSID) */
> + rldic r12, r11, 56 - 36, 36
> + or r10, r10, r12
> + slbie r10
> +
> + isync
> +
> + /* Fill SLB with our shadow */
> +
> + lbz r12, PACA_KVM_SLB_MAX(r13)
> + mulli r12, r12, 16
> + addir12, r12, PACA_KVM_SLB
> + add r12, r12, r13
> +
> + /* for (r11 = kvm_slb; r11 < kvm_slb + kvm_slb_size; r11+=slb_entry) */
> + li r11, PACA_KVM_SLB
> + add r11, r11, r13
> +
> +slb_loop_enter:
> +
> + ld r10, 0(r11)
> +
> + rldicl. r0, r10, 37, 63
> + beq slb_loop_enter_skip
> +
> + ld r9, 8(r11)
> + slbmte r9, r10
If you're updating the first 3 slbs, you need to make sure the slb
shadow is updated at the same time (BTW dumb question: can we run this
under PHYP?)
> +
> +slb_loop_enter_skip:
> +
