From patchwork Tue May 30 15:08:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Mostafa Saleh X-Patchwork-Id: 13260444 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 0E0D0C7EE23 for ; Tue, 30 May 2023 15:09:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:From:Subject:Message-ID: Mime-Version:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: References:List-Owner; bh=Usj5qde0R8qs1m1y9yLh77eICq5MGVlnhx+6hx7S8hg=; b=oiv FOgDh8PUKj++dCAyHZlc8cShIoXDoiA7XTD6ub2BMg1Cde2BmP8K22ea15UpPiS/mWZklmSmMwgt5 sOvQbwFKDqdLW46XJFxtVEkTeAoA77/lP1Ij9lw76iB7WrbHlVqdCCljjYkF8S1dyjK2rCH+novn0 oe/t71YDrkBjqRGkGmscnxlrnxPt0RQgMPE4cdnYGBvEkNkRic9Gqt3S2jCVkZhiJGJPFB5sSHY1S XzhBhR88JA/BvTZpOZoiu+z/kr/W0cp+dqRoO+o7hgxmGvB9nLqEftm8JLTQ5rA5gVQm55xRj/kBG v6yCHGmKcl82NLF0qkLB4zOMs3QLTGA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1q40y1-00ELop-2N; Tue, 30 May 2023 15:08:57 +0000 Received: from mail-wr1-x449.google.com ([2a00:1450:4864:20::449]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1q40xy-00ELo6-2R for linux-arm-kernel@lists.infradead.org; Tue, 30 May 2023 15:08:56 +0000 Received: by mail-wr1-x449.google.com with SMTP id ffacd0b85a97d-30793c16c78so6314498f8f.3 for ; Tue, 30 May 2023 08:08:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1685459331; x=1688051331; h=content-transfer-encoding:cc:to:from:subject:message-id :mime-version:date:from:to:cc:subject:date:message-id:reply-to; bh=INyGt+QwuTfaFJp7EMJqWEOGoXUhxd+HBtKKNdnZww4=; b=KCvwHCzwHpZZcpBVv1I1bLVHxO8Xn2ykPeOkv2+KApmacnGFPK6nf/m23byfUEnWss JPn9KobcIzYTNjur4ig/onz6AWeR5RNE0aknK92u/onIH9hZ59bkBT/Z3kS42C5bDN2G ijShs3+RjX/Kyug5HfHwMD6rf945IC5Rb60s1gop/te04Uwtr84EwbUEs7YrUqnreG/n eREjm5sR5mqfWssu4wU3/quLaDOUC7QKSQaaiRRHSnhoF7+f+cK+dVXqf95XrN8AdMiI 1I08XmHJ2RwLI/M0G/GOXG10F6zNKZxndz8fVfWBLLp0OgpDirhtbwh8taxNGl9nduTd AuiA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1685459331; x=1688051331; h=content-transfer-encoding:cc:to:from:subject:message-id :mime-version:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=INyGt+QwuTfaFJp7EMJqWEOGoXUhxd+HBtKKNdnZww4=; b=EwPr4V587DhdsTbEIo9KkzFjUOn4sAe4aUyV3aMzReR27U9dRpcUMUyk99Rm1aYuUR tgp0eG/CbkadgNSu9UyfS1Ez0cFA3s8uNrtU0cl4gMcJDpTZfuWzfTekQxHnT3j0Edag VaBxyn+sJs+hO00RR4EBEDEMLqOZUm37KT6/SCuiiPQA+rlYaWQZivdR/eFI3YqNTO4Q hqSwEO+5LMWuorITxuC+0OnjqNWqRtyE9weOh8Ilx0BEy/aKov7v1YVasTuA1h3xQbox S+yeMk3z+ZXITR1t/aWu9gqnqFyDtcXYcJZdM3lpbMeEf/G2YDSLkJCq54gml3uFfBfg yPsA== X-Gm-Message-State: AC+VfDyOBm8qRMoxUp6/WkCoxtidowTGfIxCxT61DhAQ2Po8GxYO65Or UAt4HNhl5c9V2qXp1tHhFweviOtSMHMi7Q== X-Google-Smtp-Source: ACHHUZ7trUbccosip83Jp1hHUHvUBBwTyfaeunBbCnY0yI3RJzF02Xs+ZkFq/94n82IAdm05j7g66a3Ser3rDQ== X-Received: from mostafa.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:333c]) (user=smostafa job=sendgmr) by 2002:a05:6000:46:b0:30a:b030:9ce1 with SMTP id k6-20020a056000004600b0030ab0309ce1mr431213wrx.5.1685459330796; Tue, 30 May 2023 08:08:50 -0700 (PDT) Date: Tue, 30 May 2023 15:08:45 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.41.0.rc0.172.g3f132b7071-goog Message-ID: <20230530150845.2856828-1-smostafa@google.com> Subject: [PATCH v3] KVM: arm64: Use BTI for nvhe From: Mostafa Saleh To: maz@kernel.org, oliver.upton@linux.dev, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org Cc: tabba@google.com, qperret@google.com, will@kernel.org, catalin.marinas@arm.com, yuzenghui@huawei.com, suzuki.poulose@arm.com, james.morse@arm.com, bgardon@google.com, gshan@redhat.com, Mostafa Saleh X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230530_080854_812445_AD35232F X-CRM114-Status: GOOD ( 19.54 ) 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 CONFIG_ARM64_BTI_KERNEL compiles the kernel to support ARMv8.5-BTI. However, the nvhe code doesn't make use of it as it doesn't map any pages with Guarded Page(GP) bit. kvm pgtable code is modified to map executable pages with GP bit if BTI is enabled for the kernel. At hyp init, SCTLR_EL2.BT is set to 1 to match EL1 configuration (SCTLR_EL1.BT1) set in bti_enable(). One difference between kernel and nvhe code, is that the kernel maps .text with GP while nvhe maps all the executable pages, this makes nvhe code need to deal with special initialization code coming from other executable sections (.idmap.text). For this we need to add bti instruction at the beginning of __kvm_handle_stub_hvc as it can be called by __host_hvc through branch instruction(br) and unlike SYM_FUNC_START, SYM_CODE_START doesn’t add bti instruction at the beginning, and it can’t be modified to add it as it is used with vector tables. Another solution which is more intrusive is to convert __kvm_handle_stub_hvc to a function and inject “bti jc” instead of “bti c” in SYM_FUNC_START Signed-off-by: Mostafa Saleh --- v2 -> v3: - Map all executable pages with GP bit instead of just .text, this simplifies the code and avoids hacks in pgtable code. v1 -> v2: - Enable BTI for nvhe also. - Only set GP bit for executable pages from pgtable code. - Set SCTLR_EL2.BT when BTI is used. - use system_supports_bti() for consistency. - Add hyp_init_valid_leaf_pte. v1: https://lore.kernel.org/all/20230516141846.792193-1-smostafa@google.com/ --- arch/arm64/include/asm/sysreg.h | 1 + arch/arm64/kvm/hyp/nvhe/hyp-init.S | 12 ++++++++++++ arch/arm64/kvm/hyp/pgtable.c | 7 ++++++- 3 files changed, 19 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index e72d9aaab6b1..204124ce86c4 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -558,6 +558,7 @@ (BIT(18)) | (BIT(22)) | (BIT(23)) | (BIT(28)) | \ (BIT(29))) +#define SCTLR_EL2_BT (BIT(36)) #ifdef CONFIG_CPU_BIG_ENDIAN #define ENDIAN_SET_EL2 SCTLR_ELx_EE #else diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S index a6d67c2bb5ae..f3ee66aa2f9d 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S +++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S @@ -128,6 +128,13 @@ alternative_if ARM64_HAS_ADDRESS_AUTH SCTLR_ELx_ENDA | SCTLR_ELx_ENDB) orr x0, x0, x1 alternative_else_nop_endif + +#ifdef CONFIG_ARM64_BTI_KERNEL +alternative_if ARM64_BTI + orr x0, x0, #SCTLR_EL2_BT +alternative_else_nop_endif +#endif /* CONFIG_ARM64_BTI_KERNEL */ + msr sctlr_el2, x0 isb @@ -196,6 +203,11 @@ SYM_CODE_START_LOCAL(__kvm_hyp_init_cpu) SYM_CODE_END(__kvm_hyp_init_cpu) SYM_CODE_START(__kvm_handle_stub_hvc) + /* + * __kvm_handle_stub_hvc called from __host_hvc through branch instruction(br) so + * we need bti j at beginning. + */ + bti j cmp x0, #HVC_SOFT_RESTART b.ne 1f diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index 3d61bd3e591d..a79a45fc4047 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -34,7 +34,7 @@ #define KVM_PTE_LEAF_ATTR_LO_S2_SH_IS 3 #define KVM_PTE_LEAF_ATTR_LO_S2_AF BIT(10) -#define KVM_PTE_LEAF_ATTR_HI GENMASK(63, 51) +#define KVM_PTE_LEAF_ATTR_HI GENMASK(63, 50) #define KVM_PTE_LEAF_ATTR_HI_SW GENMASK(58, 55) @@ -42,6 +42,8 @@ #define KVM_PTE_LEAF_ATTR_HI_S2_XN BIT(54) +#define KVM_PTE_LEAF_ATTR_HI_S1_GP BIT(50) + #define KVM_PTE_LEAF_ATTR_S2_PERMS (KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | \ KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | \ KVM_PTE_LEAF_ATTR_HI_S2_XN) @@ -371,6 +373,9 @@ static int hyp_set_prot_attr(enum kvm_pgtable_prot prot, kvm_pte_t *ptep) if (device) return -EINVAL; + + if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL) && system_supports_bti()) + attr |= KVM_PTE_LEAF_ATTR_HI_S1_GP; } else { attr |= KVM_PTE_LEAF_ATTR_HI_S1_XN; }