From patchwork Sat Jul 19 07:59:34 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Mackerras X-Patchwork-Id: 371780 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 9BBF514013F for ; Sat, 19 Jul 2014 17:59:58 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751908AbaGSH7v (ORCPT ); Sat, 19 Jul 2014 03:59:51 -0400 Received: from ozlabs.org ([103.22.144.67]:59898 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753234AbaGSH7u (ORCPT ); Sat, 19 Jul 2014 03:59:50 -0400 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPSA id 8F22814013F; Sat, 19 Jul 2014 17:59:48 +1000 (EST) From: Paul Mackerras To: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org Cc: Alexander Graf Subject: [PATCH 1/3] KVM: PPC: Book3S: Fix LPCR one_reg interface Date: Sat, 19 Jul 2014 17:59:34 +1000 Message-Id: <1405756776-7634-2-git-send-email-paulus@samba.org> X-Mailer: git-send-email 2.0.1 In-Reply-To: <1405756776-7634-1-git-send-email-paulus@samba.org> References: <1405756776-7634-1-git-send-email-paulus@samba.org> Sender: kvm-ppc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org From: Alexey Kardashevskiy Unfortunately, the LPCR got defined as a 32-bit register in the one_reg interface. This is unfortunate because KVM allows userspace to control the DPFD (default prefetch depth) field, which is in the upper 32 bits. The result is that DPFD always get set to 0, which reduces performance in the guest. We can't just change KVM_REG_PPC_LPCR to be a 64-bit register ID, since that would break existing userspace binaries. Instead we define a new KVM_REG_PPC_LPCR_64 id which is 64-bit. Userspace can still use the old KVM_REG_PPC_LPCR id, but it now only modifies those fields in the bottom 32 bits that userspace can modify (ILE, TC and AIL). If userspace uses the new KVM_REG_PPC_LPCR_64 id, it can modify DPFD as well. Signed-off-by: Alexey Kardashevskiy Signed-off-by: Paul Mackerras --- Documentation/virtual/kvm/api.txt | 3 ++- arch/powerpc/include/uapi/asm/kvm.h | 1 + arch/powerpc/kvm/book3s_hv.c | 13 +++++++++++-- arch/powerpc/kvm/book3s_pr.c | 2 ++ 4 files changed, 16 insertions(+), 3 deletions(-) diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 6955318..884f819 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -1869,7 +1869,8 @@ registers, find a list below: PPC | KVM_REG_PPC_PID | 64 PPC | KVM_REG_PPC_ACOP | 64 PPC | KVM_REG_PPC_VRSAVE | 32 - PPC | KVM_REG_PPC_LPCR | 64 + PPC | KVM_REG_PPC_LPCR | 32 + PPC | KVM_REG_PPC_LPCR_64 | 64 PPC | KVM_REG_PPC_PPR | 64 PPC | KVM_REG_PPC_ARCH_COMPAT 32 PPC | KVM_REG_PPC_DABRX | 32 diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h index 2bc4a94..de7d426 100644 --- a/arch/powerpc/include/uapi/asm/kvm.h +++ b/arch/powerpc/include/uapi/asm/kvm.h @@ -548,6 +548,7 @@ struct kvm_get_htab_header { #define KVM_REG_PPC_VRSAVE (KVM_REG_PPC | KVM_REG_SIZE_U32 | 0xb4) #define KVM_REG_PPC_LPCR (KVM_REG_PPC | KVM_REG_SIZE_U32 | 0xb5) +#define KVM_REG_PPC_LPCR_64 (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0xb5) #define KVM_REG_PPC_PPR (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0xb6) /* Architecture compatibility level */ diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index f1281c4..0c5266e 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -863,7 +863,8 @@ static int kvm_arch_vcpu_ioctl_set_sregs_hv(struct kvm_vcpu *vcpu, return 0; } -static void kvmppc_set_lpcr(struct kvm_vcpu *vcpu, u64 new_lpcr) +static void kvmppc_set_lpcr(struct kvm_vcpu *vcpu, u64 new_lpcr, + bool preserve_top32) { struct kvmppc_vcore *vc = vcpu->arch.vcore; u64 mask; @@ -898,6 +899,10 @@ static void kvmppc_set_lpcr(struct kvm_vcpu *vcpu, u64 new_lpcr) mask = LPCR_DPFD | LPCR_ILE | LPCR_TC; if (cpu_has_feature(CPU_FTR_ARCH_207S)) mask |= LPCR_AIL; + + /* Broken 32-bit version of LPCR must not clear top bits */ + if (preserve_top32) + mask &= 0xFFFFFFFF; vc->lpcr = (vc->lpcr & ~mask) | (new_lpcr & mask); spin_unlock(&vc->lock); } @@ -1011,6 +1016,7 @@ static int kvmppc_get_one_reg_hv(struct kvm_vcpu *vcpu, u64 id, *val = get_reg_val(id, vcpu->arch.vcore->tb_offset); break; case KVM_REG_PPC_LPCR: + case KVM_REG_PPC_LPCR_64: *val = get_reg_val(id, vcpu->arch.vcore->lpcr); break; case KVM_REG_PPC_PPR: @@ -1216,7 +1222,10 @@ static int kvmppc_set_one_reg_hv(struct kvm_vcpu *vcpu, u64 id, ALIGN(set_reg_val(id, *val), 1UL << 24); break; case KVM_REG_PPC_LPCR: - kvmppc_set_lpcr(vcpu, set_reg_val(id, *val)); + kvmppc_set_lpcr(vcpu, set_reg_val(id, *val), true); + break; + case KVM_REG_PPC_LPCR_64: + kvmppc_set_lpcr(vcpu, set_reg_val(id, *val), false); break; case KVM_REG_PPC_PPR: vcpu->arch.ppr = set_reg_val(id, *val); diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c index e40765f..84c7a47 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -1310,6 +1310,7 @@ static int kvmppc_get_one_reg_pr(struct kvm_vcpu *vcpu, u64 id, *val = get_reg_val(id, to_book3s(vcpu)->hior); break; case KVM_REG_PPC_LPCR: + case KVM_REG_PPC_LPCR_64: /* * We are only interested in the LPCR_ILE bit */ @@ -1345,6 +1346,7 @@ static int kvmppc_set_one_reg_pr(struct kvm_vcpu *vcpu, u64 id, to_book3s(vcpu)->hior_explicit = true; break; case KVM_REG_PPC_LPCR: + case KVM_REG_PPC_LPCR_64: kvmppc_set_lpcr_pr(vcpu, set_reg_val(id, *val)); break; default: