> 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 <ag...@suse.de> > --- > 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 0000000..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 <ag...@suse.de> > + */ > + > +/*************************************************************************** *** > + * * > + * 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 > + addi r12, 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: > + addi r11, r11, 16 > + cmpd cr0, r11, r12 > + blt slb_loop_enter > + > +slb_do_enter: > + > + /* Enter guest */ > + > + mfspr r0, SPRN_SPRG_SCRATCH0 > + > + ld r9, (PACA_EXMC+EX_R9)(r13) > + ld r10, (PACA_EXMC+EX_R10)(r13) > + ld r12, (PACA_EXMC+EX_R12)(r13) > + > + lwz r11, (PACA_EXMC+EX_CCR)(r13) > + mtcr r11 > + > + ld r11, (PACA_EXMC+EX_R3)(r13) > + mtxer r11 > + > + ld r11, (PACA_EXMC+EX_R11)(r13) > + ld r13, (PACA_EXMC+EX_R13)(r13) > + > + RFI > +kvmppc_handler_trampoline_enter_end: > + > + > + > +/*************************************************************************** *** > + * * > + * Exit code * > + * * > + *************************************************************************** **/ > + > +.global kvmppc_handler_trampoline_exit > +kvmppc_handler_trampoline_exit: > + > + /* Register usage at this point: > + * > + * SPRG_SCRATCH0 = guest R13 > + * R01 = host R1 > + * R02 = host R2 > + * R10 = guest PC > + * R11 = guest MSR > + * R12 = exit handler id > + * R13 = PACA > + * PACA.exmc.CCR = guest CR > + * PACA.exmc.R9 = guest R1 > + * PACA.exmc.R10 = guest R10 > + * PACA.exmc.R11 = guest R11 > + * PACA.exmc.R12 = guest R12 > + * PACA.exmc.R13 = guest R2 > + * > + */ > + > + /* Save registers */ > + > + std r0, (PACA_EXMC+EX_SRR0)(r13) > + std r9, (PACA_EXMC+EX_R3)(r13) > + std r10, (PACA_EXMC+EX_LR)(r13) > + std r11, (PACA_EXMC+EX_DAR)(r13) > + > + /* > + * In order for us to easily get the last instruction, > + * we got the #vmexit at, we exploit the fact that the > + * virtual layout is still the same here, so we can just > + * ld from the guest's PC address > + */ > + > + /* We only load the last instruction when it's safe */ > + cmpwi r12, BOOK3S_INTERRUPT_DATA_STORAGE > + beq ld_last_inst > + cmpwi r12, BOOK3S_INTERRUPT_PROGRAM > + beq ld_last_inst > + > + b no_ld_last_inst > + > +ld_last_inst: > + /* Save off the guest instruction we're at */ > + /* 1) enable paging for data */ > + mfmsr r9 > + ori r11, r9, MSR_DR /* Enable paging for data */ > + mtmsr r11 > + /* 2) fetch the instruction */ > + lwz r0, 0(r10) > + /* 3) disable paging again */ > + mtmsr r9 > + > +no_ld_last_inst: > + > + /* Restore bolted entries from the shadow and fix it along the way */ > + > + /* We don't store anything in entry 0, so we don't need to take care of that */ > + slbia > + isync > + > +#if SLB_NUM_BOLTED == 3 > + > + ld r11, PACA_SLBSHADOWPTR(r13) > + > + ld r10, 0x10(r11) > + cmpdi r10, 0 > + beq slb_exit_skip_1 > + oris r10, r10, slb_esi...@h > + ld r9, 0x18(r11) > + slbmte r9, r10 > + std r10, 0x10(r11) > +slb_exit_skip_1: > + > + ld r10, 0x20(r11) > + cmpdi r10, 0 > + beq slb_exit_skip_2 > + oris r10, r10, slb_esi...@h > + ld r9, 0x28(r11) > + slbmte r9, r10 > + std r10, 0x20(r11) > +slb_exit_skip_2: > + > + ld r10, 0x30(r11) > + cmpdi r10, 0 > + beq slb_exit_skip_3 > + oris r10, r10, slb_esi...@h > + ld r9, 0x38(r11) > + slbmte r9, r10 > + std r10, 0x30(r11) > +slb_exit_skip_3: Again, a macro here? > + > +#else > +#error unknown number of bolted entries > +#endif > + > +slb_do_exit: > + > + /* Restore registers */ > + > + ld r11, (PACA_EXMC+EX_DAR)(r13) > + ld r10, (PACA_EXMC+EX_LR)(r13) > + ld r9, (PACA_EXMC+EX_R3)(r13) > + > + /* Save last inst */ > + stw r0, (PACA_EXMC+EX_LR)(r13) > + > + /* Save DAR and DSISR before going to paged mode */ > + mfdar r0 > + std r0, (PACA_EXMC+EX_DAR)(r13) > + mfdsisr r0 > + stw r0, (PACA_EXMC+EX_DSISR)(r13) > + > + /* RFI into the highmem handler */ > + mfmsr r0 > + ori r0, r0, MSR_IR|MSR_DR|MSR_RI /* Enable paging */ > + mtsrr1 r0 > + ld r0, PACASAVEDMSR(r13) /* Highmem handler address */ > + mtsrr0 r0 > + > + mfspr r0, SPRN_SPRG_SCRATCH0 > + > + RFI > +kvmppc_handler_trampoline_exit_end: > + > -- > 1.6.0.2 > > _______________________________________________ > Linuxppc-dev mailing list > linuxppc-...@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/linuxppc-dev > -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
