From patchwork Mon Oct 1 09:11:18 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoffer Dall X-Patchwork-Id: 1530351 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork2.kernel.org (Postfix) with ESMTP id 662D5DF24C for ; Mon, 1 Oct 2012 09:41:58 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TIcTc-0007Z6-28; Mon, 01 Oct 2012 09:39:48 +0000 Received: from mail-qa0-f49.google.com ([209.85.216.49]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1TIc24-00069Z-By for linux-arm-kernel@lists.infradead.org; Mon, 01 Oct 2012 09:11:21 +0000 Received: by mail-qa0-f49.google.com with SMTP id a17so1306753qae.15 for ; Mon, 01 Oct 2012 02:11:20 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=subject:to:from:cc:date:message-id:in-reply-to:references :user-agent:mime-version:content-type:content-transfer-encoding :x-gm-message-state; bh=OlxhLnLmQ6gyKFAhSLIMrI108MmVarT+LL3Hz0Th0ug=; b=fgmupyP8wdliDfUVisBrG+j1vgoIplC+AJE7MDk6tzcWSKRN6vnTM0Lce7kgdHl5Qi gAxrz/TCRVZ1aoG0q5xYxk3F9I1P58nFDDQAeSTVuEc5N+IkK6Yu3sW71LRxrWdnIJ+a FRQHAXpkF8Mlj5Lrn/RnSzFHlRHaxzQTbZLwlSqDe4P0U4mBza3XzBWY+LEuwmUnNacn RJgJF5zjzo/o/6pAnshNXCoqnIaEzewTxC76B7mVZTP/AvGh7K8+uRVk6m3k2LzE1G2i 9FtQeDrPs8eY4djUCtHiw6Uo8XscG2b1R5HEFZFKHwU732ZvaXXxJdYU36n4t+sF2dQq K/NA== Received: by 10.224.202.9 with SMTP id fc9mr7062075qab.23.1349082680117; Mon, 01 Oct 2012 02:11:20 -0700 (PDT) Received: from [127.0.1.1] (pool-72-80-83-148.nycmny.fios.verizon.net. [72.80.83.148]) by mx.google.com with ESMTPS id b5sm23781713qao.13.2012.10.01.02.11.18 (version=TLSv1/SSLv3 cipher=OTHER); Mon, 01 Oct 2012 02:11:19 -0700 (PDT) Subject: [PATCH v2 11/14] KVM: ARM: Demux CCSIDR in the userspace API To: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu From: Christoffer Dall Date: Mon, 01 Oct 2012 05:11:18 -0400 Message-ID: <20121001091118.49198.68178.stgit@ubuntu> In-Reply-To: <20121001090945.49198.68950.stgit@ubuntu> References: <20121001090945.49198.68950.stgit@ubuntu> User-Agent: StGit/0.15 MIME-Version: 1.0 X-Gm-Message-State: ALoCoQlHC/YOLk1f7E223ISdEC64I8TC9+1FlC/WrfSX7AdpwNEDKsV/9kfWsTmZPAFcYa93bTOX X-Spam-Note: CRM114 invocation failed X-Spam-Score: -2.6 (--) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-2.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [209.85.216.49 listed in list.dnswl.org] -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Rusty Russell X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org The Cache Size Selection Register (CSSELR) selects the current Cache Size ID Register (CCSIDR). You write which cache you are interested in to CSSELR, and read the information out of CCSIDR. Which cache numbers are valid is known by reading the Cache Level ID Register (CLIDR). To export this state to userspace, we add a KVM_REG_ARM_DEMUX numberspace (17), which uses 8 bits to represent which register is being demultiplexed (0 for CCSIDR), and the lower 8 bits to represent this demultiplexing (in our case, the CSSELR value, which is 4 bits). Signed-off-by: Rusty Russell --- Documentation/virtual/kvm/api.txt | 2 arch/arm/include/asm/kvm.h | 9 ++ arch/arm/kvm/coproc.c | 163 ++++++++++++++++++++++++++++++++++++- 3 files changed, 171 insertions(+), 3 deletions(-) diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index c7eb72b..74223f3 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -1762,6 +1762,8 @@ ARM 32-bit CP15 registers have the following id bit patterns: ARM 64-bit CP15 registers have the following id bit patterns: 0x4003 0000 000F +ARM CCSIDR registers are demultiplexed by CSSELR value: + 0x4002 0000 0011 00 4.69 KVM_GET_ONE_REG diff --git a/arch/arm/include/asm/kvm.h b/arch/arm/include/asm/kvm.h index eb5f528..0ab12fd 100644 --- a/arch/arm/include/asm/kvm.h +++ b/arch/arm/include/asm/kvm.h @@ -87,6 +87,15 @@ struct kvm_reg_list { #define KVM_REG_ARM_CORE (0x0010 << KVM_REG_ARM_COPROC_SHIFT) #define KVM_REG_ARM_CORE_REG(name) (offsetof(struct kvm_regs, name) / 4) +/* Some registers need more space to represent values. */ +#define KVM_REG_ARM_DEMUX (0x0011 << KVM_REG_ARM_COPROC_SHIFT) +#define KVM_REG_ARM_DEMUX_ID_MASK 0x000000000000FF00 +#define KVM_REG_ARM_DEMUX_ID_SHIFT 8 +#define KVM_REG_ARM_DEMUX_ID_CCSIDR (0x00 << KVM_REG_ARM_DEMUX_ID_SHIFT) +#define KVM_REG_ARM_DEMUX_VAL_MASK 0x00000000000000FF +#define KVM_REG_ARM_DEMUX_VAL_SHIFT 0 + + /* KVM_IRQ_LINE irq field index values */ #define KVM_ARM_IRQ_TYPE_SHIFT 24 #define KVM_ARM_IRQ_TYPE_MASK 0xff diff --git a/arch/arm/kvm/coproc.c b/arch/arm/kvm/coproc.c index 3998f46..7addf62 100644 --- a/arch/arm/kvm/coproc.c +++ b/arch/arm/kvm/coproc.c @@ -35,6 +35,12 @@ * Co-processor emulation *****************************************************************************/ +/* 3 bits per cache level, as per CLIDR, but non-existent caches always 0 */ +static u32 cache_levels; + +/* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */ +#define CSSELR_MAX 12 + int kvm_handle_cp10_id(struct kvm_vcpu *vcpu, struct kvm_run *run) { kvm_inject_undefined(vcpu); @@ -548,11 +554,112 @@ static int set_invariant_cp15(u64 id, void __user *uaddr) return 0; } +static bool is_valid_cache(u32 val) +{ + u32 level, ctype; + + if (val >= CSSELR_MAX) + return -ENOENT; + + /* Bottom bit is Instruction or Data bit. Next 3 bits are level. */ + level = (val >> 1); + ctype = (cache_levels >> (level * 3)) & 7; + + switch (ctype) { + case 0: /* No cache */ + return false; + case 1: /* Instruction cache only */ + return (val & 1); + case 2: /* Data cache only */ + case 4: /* Unified cache */ + return !(val & 1); + case 3: /* Separate instruction and data caches */ + return true; + default: /* Reserved: we can't know instruction or data. */ + return false; + } +} + +/* Which cache CCSIDR represents depends on CSSELR value. */ +static u32 get_ccsidr(u32 csselr) +{ + u32 ccsidr; + + /* Make sure noone else changes CSSELR during this! */ + local_irq_disable(); + /* Put value into CSSELR */ + asm volatile("mcr p15, 2, %0, c0, c0, 0" : : "r" (csselr)); + /* Read result out of CCSIDR */ + asm volatile("mrc p15, 1, %0, c0, c0, 0" : "=r" (ccsidr)); + local_irq_enable(); + + return ccsidr; +} + +static int demux_c15_get(u64 id, void __user *uaddr) +{ + u32 val; + u32 __user *uval = uaddr; + + /* Fail if we have unknown bits set. */ + if (id & ~(KVM_REG_ARCH_MASK|KVM_REG_SIZE_MASK|KVM_REG_ARM_COPROC_MASK + | ((1 << KVM_REG_ARM_COPROC_SHIFT)-1))) + return -ENOENT; + + switch (id & KVM_REG_ARM_DEMUX_ID_MASK) { + case KVM_REG_ARM_DEMUX_ID_CCSIDR: + if (KVM_REG_SIZE(id) != 4) + return -ENOENT; + val = (id & KVM_REG_ARM_DEMUX_VAL_MASK) + >> KVM_REG_ARM_DEMUX_VAL_SHIFT; + if (!is_valid_cache(val)) + return -ENOENT; + + return put_user(get_ccsidr(val), uval); + default: + return -ENOENT; + } +} + +static int demux_c15_set(u64 id, void __user *uaddr) +{ + u32 val, newval; + u32 __user *uval = uaddr; + + /* Fail if we have unknown bits set. */ + if (id & ~(KVM_REG_ARCH_MASK|KVM_REG_SIZE_MASK|KVM_REG_ARM_COPROC_MASK + | ((1 << KVM_REG_ARM_COPROC_SHIFT)-1))) + return -ENOENT; + + switch (id & KVM_REG_ARM_DEMUX_ID_MASK) { + case KVM_REG_ARM_DEMUX_ID_CCSIDR: + if (KVM_REG_SIZE(id) != 4) + return -ENOENT; + val = (id & KVM_REG_ARM_DEMUX_VAL_MASK) + >> KVM_REG_ARM_DEMUX_VAL_SHIFT; + if (!is_valid_cache(val)) + return -ENOENT; + + if (get_user(newval, uval)) + return -EFAULT; + + /* This is also invariant: you can't change it. */ + if (newval != get_ccsidr(val)) + return -EINVAL; + return 0; + default: + return -ENOENT; + } +} + int kvm_arm_coproc_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) { const struct coproc_reg *r; void __user *uaddr = (void __user *)(long)reg->addr; + if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX) + return demux_c15_get(reg->id, uaddr); + r = index_to_coproc_reg(vcpu, reg->id); if (!r) return get_invariant_cp15(reg->id, uaddr); @@ -566,6 +673,9 @@ int kvm_arm_coproc_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) const struct coproc_reg *r; void __user *uaddr = (void __user *)(long)reg->addr; + if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX) + return demux_c15_set(reg->id, uaddr); + r = index_to_coproc_reg(vcpu, reg->id); if (!r) return set_invariant_cp15(reg->id, uaddr); @@ -574,6 +684,33 @@ int kvm_arm_coproc_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) return reg_from_user(&vcpu->arch.cp15[r->reg], uaddr, reg->id); } +static unsigned int num_demux_regs(void) +{ + unsigned int i, count = 0; + + for (i = 0; i < CSSELR_MAX; i++) + if (is_valid_cache(i)) + count++; + + return count; +} + +static int write_demux_regids(u64 __user *uindices) +{ + u64 val = KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_DEMUX; + unsigned int i; + + val |= KVM_REG_ARM_DEMUX_ID_CCSIDR; + for (i = 0; i < CSSELR_MAX; i++) { + if (!is_valid_cache(i)) + continue; + if (put_user(val | i, uindices)) + return -EFAULT; + uindices++; + } + return 0; +} + static u64 cp15_to_index(const struct coproc_reg *reg) { u64 val = KVM_REG_ARM | (15 << KVM_REG_ARM_COPROC_SHIFT); @@ -649,6 +786,7 @@ static int walk_cp15(struct kvm_vcpu *vcpu, u64 __user *uind) unsigned long kvm_arm_num_coproc_regs(struct kvm_vcpu *vcpu) { return ARRAY_SIZE(invariant_cp15) + + num_demux_regs() + walk_cp15(vcpu, (u64 __user *)NULL); } @@ -665,9 +803,11 @@ int kvm_arm_copy_coproc_indices(struct kvm_vcpu *vcpu, u64 __user *uindices) } err = walk_cp15(vcpu, uindices); - if (err > 0) - err = 0; - return err; + if (err < 0) + return err; + uindices += err; + + return write_demux_regids(uindices); } void kvm_coproc_table_init(void) @@ -681,6 +821,23 @@ void kvm_coproc_table_init(void) /* We abuse the reset function to overwrite the table itself. */ for (i = 0; i < ARRAY_SIZE(invariant_cp15); i++) invariant_cp15[i].reset(NULL, &invariant_cp15[i]); + + /* + * CLIDR format is awkward, so clean it up. See ARM B4.1.20: + * + * If software reads the Cache Type fields from Ctype1 + * upwards, once it has seen a value of 0b000, no caches + * exist at further-out levels of the hierarchy. So, for + * example, if Ctype3 is the first Cache Type field with a + * value of 0b000, the values of Ctype4 to Ctype7 must be + * ignored. + */ + asm volatile("mrc p15, 1, %0, c0, c0, 1" : "=r" (cache_levels)); + for (i = 0; i < 7; i++) + if (((cache_levels >> (i*3)) & 7) == 0) + break; + /* Clear all higher bits. */ + cache_levels &= (1 << (i*3))-1; } /**