From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de (cantor2.suse.de [195.135.220.15]) (using TLSv1 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 736301A01CE for ; Thu, 17 Jul 2014 23:56:41 +1000 (EST) Message-ID: <53C7D614.6010907@suse.de> Date: Thu, 17 Jul 2014 15:56:36 +0200 From: Alexander Graf MIME-Version: 1.0 To: Mihai Caraman , kvm-ppc@vger.kernel.org Subject: Re: [PATCH v5 3/5] KVM: PPC: Book3s: Remove kvmppc_read_inst() function References: <1405596148-1507-1-git-send-email-mihai.caraman@freescale.com> <1405596148-1507-4-git-send-email-mihai.caraman@freescale.com> In-Reply-To: <1405596148-1507-4-git-send-email-mihai.caraman@freescale.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 17.07.14 13:22, Mihai Caraman wrote: > In the context of replacing kvmppc_ld() function calls with a version of > kvmppc_get_last_inst() which allow to fail, Alex Graf suggested this: > > "If we get EMULATE_AGAIN, we just have to make sure we go back into the guest. > No need to inject an ISI into the guest - it'll do that all by itself. > With an error returning kvmppc_get_last_inst we can just use completely > get rid of kvmppc_read_inst() and only use kvmppc_get_last_inst() instead." > > As a intermediate step get rid of kvmppc_read_inst() and only use kvmppc_ld() > instead. > > Signed-off-by: Mihai Caraman > --- > v5: > - make paired single emulation the unusual > > v4: > - new patch > > arch/powerpc/kvm/book3s_pr.c | 91 ++++++++++++++++++-------------------------- > 1 file changed, 37 insertions(+), 54 deletions(-) > > diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c > index e40765f..02a983e 100644 > --- a/arch/powerpc/kvm/book3s_pr.c > +++ b/arch/powerpc/kvm/book3s_pr.c > @@ -710,42 +710,6 @@ static void kvmppc_giveup_fac(struct kvm_vcpu *vcpu, ulong fac) > #endif > } > > -static int kvmppc_read_inst(struct kvm_vcpu *vcpu) > -{ > - ulong srr0 = kvmppc_get_pc(vcpu); > - u32 last_inst = kvmppc_get_last_inst(vcpu); > - int ret; > - > - ret = kvmppc_ld(vcpu, &srr0, sizeof(u32), &last_inst, false); > - if (ret == -ENOENT) { > - ulong msr = kvmppc_get_msr(vcpu); > - > - msr = kvmppc_set_field(msr, 33, 33, 1); > - msr = kvmppc_set_field(msr, 34, 36, 0); > - msr = kvmppc_set_field(msr, 42, 47, 0); > - kvmppc_set_msr_fast(vcpu, msr); > - kvmppc_book3s_queue_irqprio(vcpu, BOOK3S_INTERRUPT_INST_STORAGE); > - return EMULATE_AGAIN; > - } > - > - return EMULATE_DONE; > -} > - > -static int kvmppc_check_ext(struct kvm_vcpu *vcpu, unsigned int exit_nr) > -{ > - > - /* Need to do paired single emulation? */ > - if (!(vcpu->arch.hflags & BOOK3S_HFLAG_PAIRED_SINGLE)) > - return EMULATE_DONE; > - > - /* Read out the instruction */ > - if (kvmppc_read_inst(vcpu) == EMULATE_DONE) > - /* Need to emulate */ > - return EMULATE_FAIL; > - > - return EMULATE_AGAIN; > -} > - > /* Handle external providers (FPU, Altivec, VSX) */ > static int kvmppc_handle_ext(struct kvm_vcpu *vcpu, unsigned int exit_nr, > ulong msr) > @@ -1149,31 +1113,49 @@ program_interrupt: > case BOOK3S_INTERRUPT_VSX: > { > int ext_msr = 0; > + int emul; > + ulong pc; > + u32 last_inst; > + > + if (vcpu->arch.hflags & BOOK3S_HFLAG_PAIRED_SINGLE) { > + /* Emulate the instruction */ If the flag is set we do paired single instruction emulation. > + > + pc = kvmppc_get_pc(vcpu); > + last_inst = kvmppc_get_last_inst(vcpu); > + emul = kvmppc_ld(vcpu, &pc, sizeof(u32), &last_inst, > + false); > + if (emul == EMULATE_DONE) > + goto program_interrupt; > + else > + r = RESUME_GUEST; > + } else { > + /* Do paired single emulation */ otherwise we deflect the interrupt into our guest. Alex > > - switch (exit_nr) { > - case BOOK3S_INTERRUPT_FP_UNAVAIL: ext_msr = MSR_FP; break; > - case BOOK3S_INTERRUPT_ALTIVEC: ext_msr = MSR_VEC; break; > - case BOOK3S_INTERRUPT_VSX: ext_msr = MSR_VSX; break; > - } > + switch (exit_nr) { > + case BOOK3S_INTERRUPT_FP_UNAVAIL: > + ext_msr = MSR_FP; > + break; > + > + case BOOK3S_INTERRUPT_ALTIVEC: > + ext_msr = MSR_VEC; > + break; > + > + case BOOK3S_INTERRUPT_VSX: > + ext_msr = MSR_VSX; > + break; > + } > > - switch (kvmppc_check_ext(vcpu, exit_nr)) { > - case EMULATE_DONE: > - /* everything ok - let's enable the ext */ > r = kvmppc_handle_ext(vcpu, exit_nr, ext_msr); > - break; > - case EMULATE_FAIL: > - /* we need to emulate this instruction */ > - goto program_interrupt; > - break; > - default: > - /* nothing to worry about - go again */ > - break; > } > break; > } > case BOOK3S_INTERRUPT_ALIGNMENT: > - if (kvmppc_read_inst(vcpu) == EMULATE_DONE) { > - u32 last_inst = kvmppc_get_last_inst(vcpu); > + { > + ulong pc = kvmppc_get_pc(vcpu); > + u32 last_inst = kvmppc_get_last_inst(vcpu); > + int emul = kvmppc_ld(vcpu, &pc, sizeof(u32), &last_inst, false); > + > + if (emul == EMULATE_DONE) { > u32 dsisr; > u64 dar; > > @@ -1187,6 +1169,7 @@ program_interrupt: > } > r = RESUME_GUEST; > break; > + } > #ifdef CONFIG_PPC_BOOK3S_64 > case BOOK3S_INTERRUPT_FAC_UNAVAIL: > kvmppc_handle_fac(vcpu, vcpu->arch.shadow_fscr >> 56);