From patchwork Mon Oct 22 06:50:15 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoffer Dall X-Patchwork-Id: 1624071 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork1.kernel.org (Postfix) with ESMTP id 6ADC5400E8 for ; Mon, 22 Oct 2012 06:56:41 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TQBtg-0001bu-DK; Mon, 22 Oct 2012 06:54:02 +0000 Received: from mail-vc0-f177.google.com ([209.85.220.177]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1TQBpu-0007vk-4q for linux-arm-kernel@lists.infradead.org; Mon, 22 Oct 2012 06:50:07 +0000 Received: by mail-vc0-f177.google.com with SMTP id p16so2566643vcq.36 for ; Sun, 21 Oct 2012 23:50:05 -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=ZH3f0Xr/g19XLGu7dYuh2l08ubUlc3JsRmXH7NJ9UUM=; b=bMDdbuo9caigBSAMc7nLK9cwzZyRcQbkOp3sUew66ie7YjzbToV3k+YyMe217FNZ4Z vR/dooK857D3M4hPz1e1gBzb8tjkvBVag26FGvOcmh0rl4a63jFRXSwF67w2Qwi6b61a uvRtWOc5W7gE6NKLzQics1ejBjG2GO+CWwsdEWfGiHiRUzo5fVi8KIoJrhJCc8WvvWxG PpP2UydbHb3U5CPWnrCklYVkTaK3uNSymbSv5E9DRnxLT35mS4bGrrlfU6/IWQAi4h8l Pli9VDHAuxKJzHwNdp4W78LBP3ff2Hg2mx4ICD4E0eyYTH6Y7nhBW9DVCKzl59BHLxRE XUCQ== Received: by 10.220.210.195 with SMTP id gl3mr13081568vcb.62.1350888605824; Sun, 21 Oct 2012 23:50:05 -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 xf2sm8957897vec.12.2012.10.21.23.50.05 (version=TLSv1/SSLv3 cipher=OTHER); Sun, 21 Oct 2012 23:50:05 -0700 (PDT) Subject: [PATCH v3 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, 22 Oct 2012 02:50:15 -0400 Message-ID: <20121022065015.18444.28460.stgit@ubuntu> In-Reply-To: <20121022064831.18444.73273.stgit@ubuntu> References: <20121022064831.18444.73273.stgit@ubuntu> User-Agent: StGit/0.15 MIME-Version: 1.0 X-Gm-Message-State: ALoCoQm2N2RC4A1knXnaX8Xu8/TgbeA/X/mTjMWcDXlJvhXAzyoVdYioCYz+j5YJKkVUpKSXPg6r 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 [209.85.220.177 listed in list.dnswl.org] -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Marcelo Tosatti , 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). Reviewed-by: Marcelo Tosatti Signed-off-by: Rusty Russell --- Documentation/virtual/kvm/api.txt | 2 arch/arm/include/uapi/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 242ff3e..6f87d61 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -1804,6 +1804,8 @@ 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/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h index 138a588c..d79d064 100644 --- a/arch/arm/include/uapi/asm/kvm.h +++ b/arch/arm/include/uapi/asm/kvm.h @@ -81,6 +81,15 @@ struct kvm_arch_memory_slot { #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 95a0f5e..9ce5861 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; } /**