From patchwork Tue Sep 3 15:38:29 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 13788963 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DD92D18B480; Tue, 3 Sep 2024 15:38:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725377923; cv=none; b=CakEBd+M6M0Mek1MobpyITdTV+GWDD2IwFedRz0HLiLkj88E3TjsRWUwk1JLmpSo4nhzAzNUusGck6B61kUgoUuYU2O4Lhqd5zbxK88hV9iVECW4ZfCdTIu7nsFmYDK5yN88go8QL3fM6pSzf1VHX3zws0TtcbjD/3Uy663TgDk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725377923; c=relaxed/simple; bh=OvhoX5Eq9pPr4X9zaRtFKmT1okoKUM0ZuTkv+nYEtb4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=uw+Jhpt2BPdMkXR4LdH8XVz0GdBj/gfeJY8HJIO8DUgQez1hjv5Pv5gwDDGTXBjoOTKKTbkoFupUCRiriJzYO0MSy74XOB9KnqXqcDrDEfWbleAjczgwQ3tldbY48CgRAM4xxl6QJx+QhJdDepjZdlQ8NgBCPuGI0yiiJS/A5II= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=r2rJYEhQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="r2rJYEhQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8E218C4CEC4; Tue, 3 Sep 2024 15:38:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725377922; bh=OvhoX5Eq9pPr4X9zaRtFKmT1okoKUM0ZuTkv+nYEtb4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=r2rJYEhQ3o4eps9Ba0LOKCb79xOiBW1rb6KdwRXQnhTBi0aucFyzlt7YahqTW/hBV VMqtvRzX1TnAswViq1w0+E4dX4yhTGXZYBYngX+Rtc0oZJ5eaT+VkunBA/K84nAudg v0LYHg9zBXYRBGcwfTwUTBb8ZNRvg8yF+GxcDc+cT/hAccChFEuQ2uej3Z0GlVRQnA FFvaoVFKU0zRjbA/tPwBFUK4JEO6dlVoA/mPlXdusi4y3xsvsvRS1dAe93gb10cIl1 k3CaFWL9bQnl/xdUNRppjYCGUpPZzM9eHdUP8NBpFSIOs8So7yPm2NMD/QLqcQUR+p bXt2eOI2Z4XBw== Received: from sofa.misterjones.org ([185.219.108.64] helo=valley-girl.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1slVc8-009Hr9-SH; Tue, 03 Sep 2024 16:38:40 +0100 From: Marc Zyngier To: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org Cc: James Morse , Suzuki K Poulose , Oliver Upton , Zenghui Yu , Joey Gouly , Alexandru Elisei , Mark Brown Subject: [PATCH v2 11/16] KVM: arm64: Split S1 permission evaluation into direct and hierarchical parts Date: Tue, 3 Sep 2024 16:38:29 +0100 Message-Id: <20240903153834.1909472-12-maz@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240903153834.1909472-1-maz@kernel.org> References: <20240903153834.1909472-1-maz@kernel.org> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, oliver.upton@linux.dev, yuzenghui@huawei.com, joey.gouly@arm.com, alexandru.elisei@arm.com, broonie@kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false The AArch64.S1DirectBasePermissions() pseudocode deals with both direct and hierarchical S1 permission evaluation. While this is probably convenient in the pseudocode, we would like a bit more flexibility to slot things like indirect permissions. To that effect, split the two permission check parts out of handle_at_slow() and into their own functions. The permissions are passed around in a new s1_perms type that contains the individual permissions across the flow. Signed-off-by: Marc Zyngier --- arch/arm64/kvm/at.c | 164 ++++++++++++++++++++++++++------------------ 1 file changed, 99 insertions(+), 65 deletions(-) diff --git a/arch/arm64/kvm/at.c b/arch/arm64/kvm/at.c index 39f0e87a340e..68f5b89598ec 100644 --- a/arch/arm64/kvm/at.c +++ b/arch/arm64/kvm/at.c @@ -47,6 +47,10 @@ struct s1_walk_result { bool failed; }; +struct s1_perms { + bool ur, uw, ux, pr, pw, px; +}; + static void fail_s1_walk(struct s1_walk_result *wr, u8 fst, bool ptw, bool s2) { wr->fst = fst; @@ -747,111 +751,141 @@ static bool pan3_enabled(struct kvm_vcpu *vcpu, enum trans_regime regime) return sctlr & SCTLR_EL1_EPAN; } -static u64 handle_at_slow(struct kvm_vcpu *vcpu, u32 op, u64 vaddr) +static void compute_s1_direct_permissions(struct kvm_vcpu *vcpu, + struct s1_walk_info *wi, + struct s1_walk_result *wr, + struct s1_perms *s1p) { - bool perm_fail, ur, uw, ux, pr, pw, px; - struct s1_walk_result wr = {}; - struct s1_walk_info wi = {}; - int ret, idx; - - ret = setup_s1_walk(vcpu, op, &wi, &wr, vaddr); - if (ret) - goto compute_par; - - if (wr.level == S1_MMU_DISABLED) - goto compute_par; - - idx = srcu_read_lock(&vcpu->kvm->srcu); - - ret = walk_s1(vcpu, &wi, &wr, vaddr); - - srcu_read_unlock(&vcpu->kvm->srcu, idx); - - if (ret) - goto compute_par; - - /* FIXME: revisit when adding indirect permission support */ - /* AArch64.S1DirectBasePermissions() */ - if (wi.regime != TR_EL2) { - switch (FIELD_GET(PTE_USER | PTE_RDONLY, wr.desc)) { + /* Non-hierarchical part of AArch64.S1DirectBasePermissions() */ + if (wi->regime != TR_EL2) { + switch (FIELD_GET(PTE_USER | PTE_RDONLY, wr->desc)) { case 0b00: - pr = pw = true; - ur = uw = false; + s1p->pr = s1p->pw = true; + s1p->ur = s1p->uw = false; break; case 0b01: - pr = pw = ur = uw = true; + s1p->pr = s1p->pw = s1p->ur = s1p->uw = true; break; case 0b10: - pr = true; - pw = ur = uw = false; + s1p->pr = true; + s1p->pw = s1p->ur = s1p->uw = false; break; case 0b11: - pr = ur = true; - pw = uw = false; + s1p->pr = s1p->ur = true; + s1p->pw = s1p->uw = false; break; } - switch (wr.APTable) { + /* We don't use px for anything yet, but hey... */ + s1p->px = !((wr->desc & PTE_PXN) || s1p->uw); + s1p->ux = !(wr->desc & PTE_UXN); + } else { + s1p->ur = s1p->uw = s1p->ux = false; + + if (!(wr->desc & PTE_RDONLY)) { + s1p->pr = s1p->pw = true; + } else { + s1p->pr = true; + s1p->pw = false; + } + + /* XN maps to UXN */ + s1p->px = !(wr->desc & PTE_UXN); + } +} + +static void compute_s1_hierarchical_permissions(struct kvm_vcpu *vcpu, + struct s1_walk_info *wi, + struct s1_walk_result *wr, + struct s1_perms *s1p) +{ + /* Hierarchical part of AArch64.S1DirectBasePermissions() */ + if (wi->regime != TR_EL2) { + switch (wr->APTable) { case 0b00: break; case 0b01: - ur = uw = false; + s1p->ur = s1p->uw = false; break; case 0b10: - pw = uw = false; + s1p->pw = s1p->uw = false; break; case 0b11: - pw = ur = uw = false; + s1p->pw = s1p->ur = s1p->uw = false; break; } - /* We don't use px for anything yet, but hey... */ - px = !((wr.desc & PTE_PXN) || wr.PXNTable || uw); - ux = !((wr.desc & PTE_UXN) || wr.UXNTable); - - if (op == OP_AT_S1E1RP || op == OP_AT_S1E1WP) { - bool pan; - - pan = *vcpu_cpsr(vcpu) & PSR_PAN_BIT; - pan &= ur || uw || (pan3_enabled(vcpu, wi.regime) && ux); - pw &= !pan; - pr &= !pan; - } + s1p->px &= !wr->PXNTable; + s1p->ux &= !wr->UXNTable; } else { - ur = uw = ux = false; + if (wr->APTable & BIT(1)) + s1p->pw = false; - if (!(wr.desc & PTE_RDONLY)) { - pr = pw = true; - } else { - pr = true; - pw = false; - } + /* XN maps to UXN */ + s1p->px &= !wr->UXNTable; + } +} - if (wr.APTable & BIT(1)) - pw = false; +static void compute_s1_permissions(struct kvm_vcpu *vcpu, u32 op, + struct s1_walk_info *wi, + struct s1_walk_result *wr, + struct s1_perms *s1p) +{ + compute_s1_direct_permissions(vcpu, wi, wr, s1p); + compute_s1_hierarchical_permissions(vcpu, wi, wr, s1p); - /* XN maps to UXN */ - px = !((wr.desc & PTE_UXN) || wr.UXNTable); + if (op == OP_AT_S1E1RP || op == OP_AT_S1E1WP) { + bool pan; + + pan = *vcpu_cpsr(vcpu) & PSR_PAN_BIT; + pan &= s1p->ur || s1p->uw || (pan3_enabled(vcpu, wi->regime) && s1p->ux); + s1p->pw &= !pan; + s1p->pr &= !pan; } +} + +static u64 handle_at_slow(struct kvm_vcpu *vcpu, u32 op, u64 vaddr) +{ + struct s1_walk_result wr = {}; + struct s1_walk_info wi = {}; + struct s1_perms s1p = {}; + bool perm_fail = false; + int ret, idx; + + ret = setup_s1_walk(vcpu, op, &wi, &wr, vaddr); + if (ret) + goto compute_par; + + if (wr.level == S1_MMU_DISABLED) + goto compute_par; + + idx = srcu_read_lock(&vcpu->kvm->srcu); + + ret = walk_s1(vcpu, &wi, &wr, vaddr); + + srcu_read_unlock(&vcpu->kvm->srcu, idx); + + if (ret) + goto compute_par; - perm_fail = false; + compute_s1_permissions(vcpu, op, &wi, &wr, &s1p); switch (op) { case OP_AT_S1E1RP: case OP_AT_S1E1R: case OP_AT_S1E2R: - perm_fail = !pr; + perm_fail = !s1p.pr; break; case OP_AT_S1E1WP: case OP_AT_S1E1W: case OP_AT_S1E2W: - perm_fail = !pw; + perm_fail = !s1p.pw; break; case OP_AT_S1E0R: - perm_fail = !ur; + perm_fail = !s1p.ur; break; case OP_AT_S1E0W: - perm_fail = !uw; + perm_fail = !s1p.uw; break; case OP_AT_S1E1A: case OP_AT_S1E2A: