From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935400AbaICXKG (ORCPT ); Wed, 3 Sep 2014 19:10:06 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:46063 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933487AbaICWSj (ORCPT ); Wed, 3 Sep 2014 18:18:39 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexey Kardashevskiy , Paul Mackerras , Alexander Graf Subject: [PATCH 3.16 059/125] KVM: PPC: Book3S: Fix LPCR one_reg interface Date: Wed, 3 Sep 2014 15:06:56 -0700 Message-Id: <20140903220625.449056707@linuxfoundation.org> X-Mailer: git-send-email 2.1.0 In-Reply-To: <20140903220623.649748296@linuxfoundation.org> References: <20140903220623.649748296@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexey Kardashevskiy commit a0840240c0c6bcbac8f0f5db11f95c19aaf9b52f upstream. 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 Signed-off-by: Alexander Graf Signed-off-by: Greg Kroah-Hartman --- 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(-) --- 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 --- 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 */ --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -785,7 +785,8 @@ static int kvm_arch_vcpu_ioctl_set_sregs 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; @@ -820,6 +821,10 @@ static void kvmppc_set_lpcr(struct kvm_v 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); } @@ -939,6 +944,7 @@ static int kvmppc_get_one_reg_hv(struct *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: @@ -1150,7 +1156,10 @@ static int kvmppc_set_one_reg_hv(struct 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); --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -1233,6 +1233,7 @@ static int kvmppc_get_one_reg_pr(struct *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 */ @@ -1268,6 +1269,7 @@ static int kvmppc_set_one_reg_pr(struct 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: