From patchwork Fri Oct 25 18:23:36 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Upton X-Patchwork-Id: 13851330 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5D7F5D149E7 for ; Fri, 25 Oct 2024 19:03:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=AENT3HV05ZYgfYGtK7xFvzc3fnZN0pfnRLgWILAuZnQ=; b=S8NhKZsXEPe3ubilZTXOW+Bq84 qTDwyTLWxpTbuCkAhDLJi1fvVvixKNmD79YJBa2iRPt0B9EHp5pVDuC0yYTXPTioTaA+a3TBZLktA uNOW2TqP2nDZqCH+gXALjGLAmJVbAHW3TGPM8lfaeplLSpBRQu6iRIkj668ugv6F2mZkWYqjVgksO 1Fe6XU+AteEU+Jl54GalZ6XxLacnrjwN469BIfcaU6nt69FnXS+1O7EiToHlQ/q04S3DQQzOXdpVM QsbOrc7wyQzc37riLoBoxzWH+JGTLbz4zWykIQUbNLwt9c+gkZ7D7vCzPasgLHXEYBSK8HwTsZANU 1RZdJ33Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t4PaP-00000004tEb-3qM2; Fri, 25 Oct 2024 19:03:01 +0000 Received: from out-183.mta1.migadu.com ([2001:41d0:203:375::b7]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t4Oyo-00000004mmO-3TiH for linux-arm-kernel@lists.infradead.org; Fri, 25 Oct 2024 18:24:12 +0000 X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1729880648; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=AENT3HV05ZYgfYGtK7xFvzc3fnZN0pfnRLgWILAuZnQ=; b=J9K565V5Mp1DK+wZq8UNE8ZhLwLNylJy4zux1sSKU6e9q/asZkxef2QDlnTmHlez3xIKcR 8Un/4YcuL2+92GFzohCcrXuwYh0sNgMbMX3O8GMiEkZl9zhxqWcZMBNJBwZFh3VzmXrht1 8sHA075HhzvHi20Sxz5ES3vHtFQ0MN4= From: Oliver Upton To: kvmarm@lists.linux.dev Cc: Marc Zyngier , Joey Gouly , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Anshuman Khandual , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Oliver Upton Subject: [PATCH v4 01/18] KVM: arm64: Extend masking facility to arbitrary registers Date: Fri, 25 Oct 2024 18:23:36 +0000 Message-ID: <20241025182354.3364124-2-oliver.upton@linux.dev> In-Reply-To: <20241025182354.3364124-1-oliver.upton@linux.dev> References: <20241025182354.3364124-1-oliver.upton@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241025_112411_179828_8D701BD7 X-CRM114-Status: GOOD ( 15.92 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Marc Zyngier We currently only use the masking (RES0/RES1) facility for VNCR registers, as they are memory-based and thus easy to sanitise. But we could apply the same thing to other registers if we: - split the sanitisation from __VNCR_START__ - apply the sanitisation when reading from a HW register This involves a new "marker" in the vcpu_sysreg enum, which defines the point at which the sanitisation applies (the VNCR registers being of course after this marker). Whle we are at it, rename kvm_vcpu_sanitise_vncr_reg() to kvm_vcpu_apply_reg_masks(), which is vaguely more explicit, and harden set_sysreg_masks() against setting masks for random registers... Signed-off-by: Marc Zyngier Reviewed-by: Joey Gouly Signed-off-by: Oliver Upton --- arch/arm64/include/asm/kvm_host.h | 19 +++++++++++++------ arch/arm64/kvm/nested.c | 12 ++++++++---- arch/arm64/kvm/sys_regs.c | 3 +++ 3 files changed, 24 insertions(+), 10 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 94cff508874b..07c7d2b7b3a3 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -367,7 +367,7 @@ struct kvm_arch { u64 ctr_el0; - /* Masks for VNCR-baked sysregs */ + /* Masks for VNCR-backed and general EL2 sysregs */ struct kvm_sysreg_masks *sysreg_masks; /* @@ -401,6 +401,9 @@ struct kvm_vcpu_fault_info { r = __VNCR_START__ + ((VNCR_ ## r) / 8), \ __after_##r = __MAX__(__before_##r - 1, r) +#define MARKER(m) \ + m, __after_##m = m - 1 + enum vcpu_sysreg { __INVALID_SYSREG__, /* 0 is reserved as an invalid value */ MPIDR_EL1, /* MultiProcessor Affinity Register */ @@ -487,7 +490,11 @@ enum vcpu_sysreg { CNTHV_CTL_EL2, CNTHV_CVAL_EL2, - __VNCR_START__, /* Any VNCR-capable reg goes after this point */ + /* Anything from this can be RES0/RES1 sanitised */ + MARKER(__SANITISED_REG_START__), + + /* Any VNCR-capable reg goes after this point */ + MARKER(__VNCR_START__), VNCR(SCTLR_EL1),/* System Control Register */ VNCR(ACTLR_EL1),/* Auxiliary Control Register */ @@ -547,7 +554,7 @@ struct kvm_sysreg_masks { struct { u64 res0; u64 res1; - } mask[NR_SYS_REGS - __VNCR_START__]; + } mask[NR_SYS_REGS - __SANITISED_REG_START__]; }; struct kvm_cpu_context { @@ -995,13 +1002,13 @@ static inline u64 *___ctxt_sys_reg(const struct kvm_cpu_context *ctxt, int r) #define ctxt_sys_reg(c,r) (*__ctxt_sys_reg(c,r)) -u64 kvm_vcpu_sanitise_vncr_reg(const struct kvm_vcpu *, enum vcpu_sysreg); +u64 kvm_vcpu_apply_reg_masks(const struct kvm_vcpu *, enum vcpu_sysreg, u64); #define __vcpu_sys_reg(v,r) \ (*({ \ const struct kvm_cpu_context *ctxt = &(v)->arch.ctxt; \ u64 *__r = __ctxt_sys_reg(ctxt, (r)); \ - if (vcpu_has_nv((v)) && (r) >= __VNCR_START__) \ - *__r = kvm_vcpu_sanitise_vncr_reg((v), (r)); \ + if (vcpu_has_nv((v)) && (r) >= __SANITISED_REG_START__) \ + *__r = kvm_vcpu_apply_reg_masks((v), (r), *__r);\ __r; \ })) diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c index f9e30dd34c7a..b20b3bfb9cae 100644 --- a/arch/arm64/kvm/nested.c +++ b/arch/arm64/kvm/nested.c @@ -908,15 +908,15 @@ static void limit_nv_id_regs(struct kvm *kvm) kvm_set_vm_id_reg(kvm, SYS_ID_AA64DFR0_EL1, val); } -u64 kvm_vcpu_sanitise_vncr_reg(const struct kvm_vcpu *vcpu, enum vcpu_sysreg sr) +u64 kvm_vcpu_apply_reg_masks(const struct kvm_vcpu *vcpu, + enum vcpu_sysreg sr, u64 v) { - u64 v = ctxt_sys_reg(&vcpu->arch.ctxt, sr); struct kvm_sysreg_masks *masks; masks = vcpu->kvm->arch.sysreg_masks; if (masks) { - sr -= __VNCR_START__; + sr -= __SANITISED_REG_START__; v &= ~masks->mask[sr].res0; v |= masks->mask[sr].res1; @@ -927,7 +927,11 @@ u64 kvm_vcpu_sanitise_vncr_reg(const struct kvm_vcpu *vcpu, enum vcpu_sysreg sr) static void set_sysreg_masks(struct kvm *kvm, int sr, u64 res0, u64 res1) { - int i = sr - __VNCR_START__; + int i = sr - __SANITISED_REG_START__; + + BUILD_BUG_ON(!__builtin_constant_p(sr)); + BUILD_BUG_ON(sr < __SANITISED_REG_START__); + BUILD_BUG_ON(sr >= NR_SYS_REGS); kvm->arch.sysreg_masks->mask[i].res0 = res0; kvm->arch.sysreg_masks->mask[i].res1 = res1; diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index dad88e31f953..30fe940cd5bd 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -165,6 +165,9 @@ u64 vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg) /* Get the current version of the EL1 counterpart. */ WARN_ON(!__vcpu_read_sys_reg_from_cpu(el1r, &val)); + if (reg >= __SANITISED_REG_START__) + val = kvm_vcpu_apply_reg_masks(vcpu, reg, val); + return val; }