From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Huth Subject: [PATCH] KVM: PPC: Book3S PR: Do not fail emulation with mtspr/mfspr for unknown SPRs Date: Mon, 3 Apr 2017 13:23:15 +0200 Message-ID: <1491218595-10943-1-git-send-email-thuth@redhat.com> Cc: kvm@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Laurent Vivier To: Paul Mackerras , kvm-ppc@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:42346 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752038AbdDCLX1 (ORCPT ); Mon, 3 Apr 2017 07:23:27 -0400 Sender: kvm-owner@vger.kernel.org List-ID: According to the PowerISA 2.07, mtspr and mfspr should not generate an illegal instruction exception when being used with an undefined SPR, but rather treat the instruction as a NOP, inject a privilege exception or an emulation assistance exception - depending on the SPR number. Also turn the printk here into a ratelimited print statement, so that the guest can not flood the dmesg log of the host by issueing lots of illegal mtspr/mfspr instruction here. Signed-off-by: Thomas Huth --- arch/powerpc/kvm/book3s.c | 1 + arch/powerpc/kvm/book3s_emulate.c | 30 ++++++++++++++++++++++-------- 2 files changed, 23 insertions(+), 8 deletions(-) diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c index b6b5c18..9b007f9 100644 --- a/arch/powerpc/kvm/book3s.c +++ b/arch/powerpc/kvm/book3s.c @@ -137,6 +137,7 @@ void kvmppc_inject_interrupt(struct kvm_vcpu *vcpu, int vec, u64 flags) kvmppc_set_pc(vcpu, kvmppc_interrupt_offset(vcpu) + vec); vcpu->arch.mmu.reset_msr(vcpu); } +EXPORT_SYMBOL_GPL(kvmppc_inject_interrupt); static int kvmppc_book3s_vec2irqprio(unsigned int vec) { diff --git a/arch/powerpc/kvm/book3s_emulate.c b/arch/powerpc/kvm/book3s_emulate.c index 8359752..9c31e23 100644 --- a/arch/powerpc/kvm/book3s_emulate.c +++ b/arch/powerpc/kvm/book3s_emulate.c @@ -503,10 +503,16 @@ int kvmppc_core_emulate_mtspr_pr(struct kvm_vcpu *vcpu, int sprn, ulong spr_val) break; unprivileged: default: - printk(KERN_INFO "KVM: invalid SPR write: %d\n", sprn); -#ifndef DEBUG_SPR - emulated = EMULATE_FAIL; -#endif + pr_info_ratelimited("KVM: invalid SPR write: %d\n", sprn); + if (sprn & 0x10) { + if (kvmppc_get_msr(vcpu) & MSR_PR) + kvmppc_core_queue_program(vcpu, SRR1_PROGPRIV); + } else { + if ((kvmppc_get_msr(vcpu) & MSR_PR) || sprn == 0) + kvmppc_inject_interrupt(vcpu, + BOOK3S_INTERRUPT_H_EMUL_ASSIST, + 0); + } break; } @@ -648,10 +654,18 @@ int kvmppc_core_emulate_mfspr_pr(struct kvm_vcpu *vcpu, int sprn, ulong *spr_val break; default: unprivileged: - printk(KERN_INFO "KVM: invalid SPR read: %d\n", sprn); -#ifndef DEBUG_SPR - emulated = EMULATE_FAIL; -#endif + pr_info_ratelimited("KVM: invalid SPR read: %d\n", sprn); + if (sprn & 0x10) { + if (kvmppc_get_msr(vcpu) & MSR_PR) + kvmppc_core_queue_program(vcpu, SRR1_PROGPRIV); + } else { + if ((kvmppc_get_msr(vcpu) & MSR_PR) || sprn == 0 || + sprn == 4 || sprn == 5 || sprn == 6) + kvmppc_inject_interrupt(vcpu, + BOOK3S_INTERRUPT_H_EMUL_ASSIST, + 0); + } + break; } -- 1.8.3.1 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Huth Date: Mon, 03 Apr 2017 11:23:15 +0000 Subject: [PATCH] KVM: PPC: Book3S PR: Do not fail emulation with mtspr/mfspr for unknown SPRs Message-Id: <1491218595-10943-1-git-send-email-thuth@redhat.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Paul Mackerras , kvm-ppc@vger.kernel.org Cc: kvm@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Laurent Vivier According to the PowerISA 2.07, mtspr and mfspr should not generate an illegal instruction exception when being used with an undefined SPR, but rather treat the instruction as a NOP, inject a privilege exception or an emulation assistance exception - depending on the SPR number. Also turn the printk here into a ratelimited print statement, so that the guest can not flood the dmesg log of the host by issueing lots of illegal mtspr/mfspr instruction here. Signed-off-by: Thomas Huth --- arch/powerpc/kvm/book3s.c | 1 + arch/powerpc/kvm/book3s_emulate.c | 30 ++++++++++++++++++++++-------- 2 files changed, 23 insertions(+), 8 deletions(-) diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c index b6b5c18..9b007f9 100644 --- a/arch/powerpc/kvm/book3s.c +++ b/arch/powerpc/kvm/book3s.c @@ -137,6 +137,7 @@ void kvmppc_inject_interrupt(struct kvm_vcpu *vcpu, int vec, u64 flags) kvmppc_set_pc(vcpu, kvmppc_interrupt_offset(vcpu) + vec); vcpu->arch.mmu.reset_msr(vcpu); } +EXPORT_SYMBOL_GPL(kvmppc_inject_interrupt); static int kvmppc_book3s_vec2irqprio(unsigned int vec) { diff --git a/arch/powerpc/kvm/book3s_emulate.c b/arch/powerpc/kvm/book3s_emulate.c index 8359752..9c31e23 100644 --- a/arch/powerpc/kvm/book3s_emulate.c +++ b/arch/powerpc/kvm/book3s_emulate.c @@ -503,10 +503,16 @@ int kvmppc_core_emulate_mtspr_pr(struct kvm_vcpu *vcpu, int sprn, ulong spr_val) break; unprivileged: default: - printk(KERN_INFO "KVM: invalid SPR write: %d\n", sprn); -#ifndef DEBUG_SPR - emulated = EMULATE_FAIL; -#endif + pr_info_ratelimited("KVM: invalid SPR write: %d\n", sprn); + if (sprn & 0x10) { + if (kvmppc_get_msr(vcpu) & MSR_PR) + kvmppc_core_queue_program(vcpu, SRR1_PROGPRIV); + } else { + if ((kvmppc_get_msr(vcpu) & MSR_PR) || sprn = 0) + kvmppc_inject_interrupt(vcpu, + BOOK3S_INTERRUPT_H_EMUL_ASSIST, + 0); + } break; } @@ -648,10 +654,18 @@ int kvmppc_core_emulate_mfspr_pr(struct kvm_vcpu *vcpu, int sprn, ulong *spr_val break; default: unprivileged: - printk(KERN_INFO "KVM: invalid SPR read: %d\n", sprn); -#ifndef DEBUG_SPR - emulated = EMULATE_FAIL; -#endif + pr_info_ratelimited("KVM: invalid SPR read: %d\n", sprn); + if (sprn & 0x10) { + if (kvmppc_get_msr(vcpu) & MSR_PR) + kvmppc_core_queue_program(vcpu, SRR1_PROGPRIV); + } else { + if ((kvmppc_get_msr(vcpu) & MSR_PR) || sprn = 0 || + sprn = 4 || sprn = 5 || sprn = 6) + kvmppc_inject_interrupt(vcpu, + BOOK3S_INTERRUPT_H_EMUL_ASSIST, + 0); + } + break; } -- 1.8.3.1