From patchwork Fri Mar 14 00:35:15 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 14016110 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 2E4D2C282DE for ; Fri, 14 Mar 2025 00:42:32 +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:Cc:To:In-Reply-To:References :Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=UZkBOLA9X+SLYhZBjMUdi9mQ24CxFobNzZkusKMHjCs=; b=C+W5jC47OoI6VxioShXTiU+7Ln dWshyduQatvsSTbLr8khiUgLSeSMkW1kmYONxq7dDKxYJvs708jxwOtPAhgrT7sM6AV4nW84InfyI J4jPsHUy6aiWQGfp2LKqNEQGyS9dBctaEAtjSGy/WmF7pIRDzb+zR0LDF9+wsZshdasbglik+ZKff L9nHPbXRTFyBr9BXpawWYVpjHiOsMWGL8fh1eE5+T/cVjDMh3w3W6hlptfv1ND3dbiPhKY3C6IFy1 wyo2ZlnMbCvdeQMb4yGlLSnELSIs+DzN1zEE+jwOQ8dmrx0ss2kPM5N1QSnBFc+Eu8LgSRs7+TBW3 phavF9Cw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tst80-0000000CpGv-1pg6; Fri, 14 Mar 2025 00:42:20 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tst1b-0000000CoMx-1diA for linux-arm-kernel@lists.infradead.org; Fri, 14 Mar 2025 00:35:44 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 069CE5C5D78; Fri, 14 Mar 2025 00:33:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D16F7C4CEEE; Fri, 14 Mar 2025 00:35:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741912542; bh=sdmZYjSKuQYlgeObZgUxNcOjWmmjERzES6RrhaWvdbs=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=j7M3eJXhVEi6uVZTB9xmZqHMymkc0GPeayaNiqtANpkI1FJ7HyR9+giATBk7sF3gE FBmdlG7LPzuNkqILq/IRuS1qLLTHSeHmKcv+SJEwSMg5raOdv5P5EtV9SZf49d1KP7 HzYYeoD2QOnv+4vy+bWNx/3O2c7t7zi8tDCkwXxjG0jC1yxWApC9daSCUZWEz79hh0 /wbnGDMVfg2ez/HqPRCu5zKYOv87qMhxuXEW0TaX8p4uwy2QbN3OtIZjqh+yYcViui /5y9wGzQRjqhb2XLJ0BQsPyE9UhyFih1Tzeha76AYrzUqhT3NvzttSLk5/6NstQZkG 7RvsKa6mPe3lw== From: Mark Brown Date: Fri, 14 Mar 2025 00:35:15 +0000 Subject: [PATCH 6.12 3/8] KVM: arm64: Remove host FPSIMD saving for non-protected KVM MIME-Version: 1.0 Message-Id: <20250314-stable-sve-6-12-v1-3-ddc16609d9ba@kernel.org> References: <20250314-stable-sve-6-12-v1-0-ddc16609d9ba@kernel.org> In-Reply-To: <20250314-stable-sve-6-12-v1-0-ddc16609d9ba@kernel.org> To: Greg Kroah-Hartman , Marc Zyngier , Oliver Upton , Joey Gouly , Suzuki K Poulose , Catalin Marinas , Will Deacon Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Mark Brown , Mark Rutland , Fuad Tabba X-Mailer: b4 0.15-dev-1b0d6 X-Developer-Signature: v=1; a=openpgp-sha256; l=8015; i=broonie@kernel.org; h=from:subject:message-id; bh=B7wPFF9YCtOLnvOO1e5I1AsTzXQtKnhMVVgl4qZXzEw=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBn03nLrDwOKvSDQTZPZf+b5TQyfduhDYMSzj5tQ+lO 8DZtD6+JATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZ9N5ywAKCRAk1otyXVSH0MczB/ 9CI6049p0PAAl+rol27UWJXPS6g0vl1CiKPGmsFUuy3j4ZYzOLrWJll8+O54QUP/lcHklqxORGfsj0 PcWQbfogCoXW/3m6vCekyGDz0GOXJtOFDU6q2IJ1ALm6Ig6k+7M8xGvrigv8bkUKcO9qeIxtqkmJwi lnRraNw0w7vdhV6qGqXC8aBxjunl/VlhGWmaqUGRWsuwxJAOaTMEUu3py/ymc35GQp57Nc7m2xaiq3 L6aa7EeXmFV8CChd48KVSdIaU14pzZ4IefnxnFm9myH/68PasQpbd6j6c4z8E7KmMm0cQqTOMSHaeS kb0QLnaFZs3eSiL7UrfXCvfRtR25uP X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250313_173543_547886_D61CF26C X-CRM114-Status: GOOD ( 24.84 ) 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: Mark Rutland Now that the host eagerly saves its own FPSIMD/SVE/SME state, non-protected KVM never needs to save the host FPSIMD/SVE/SME state, and the code to do this is never used. Protected KVM still needs to save/restore the host FPSIMD/SVE state to avoid leaking guest state to the host (and to avoid revealing to the host whether the guest used FPSIMD/SVE/SME), and that code needs to be retained. Remove the unused code and data structures. To avoid the need for a stub copy of kvm_hyp_save_fpsimd_host() in the VHE hyp code, the nVHE/hVHE version is moved into the shared switch header, where it is only invoked when KVM is in protected mode. Signed-off-by: Mark Rutland Reviewed-by: Mark Brown Tested-by: Mark Brown Acked-by: Will Deacon Cc: Catalin Marinas Cc: Fuad Tabba Cc: Marc Zyngier Cc: Oliver Upton Reviewed-by: Oliver Upton Link: https://lore.kernel.org/r/20250210195226.1215254-3-mark.rutland@arm.com Signed-off-by: Marc Zyngier Signed-off-by: Mark Brown --- arch/arm64/include/asm/kvm_host.h | 20 +++++--------------- arch/arm64/kvm/arm.c | 8 -------- arch/arm64/kvm/fpsimd.c | 2 -- arch/arm64/kvm/hyp/include/hyp/switch.h | 25 +++++++++++++++++++++++-- arch/arm64/kvm/hyp/nvhe/hyp-main.c | 2 +- arch/arm64/kvm/hyp/nvhe/switch.c | 28 ---------------------------- arch/arm64/kvm/hyp/vhe/switch.c | 8 -------- 7 files changed, 29 insertions(+), 64 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index d148cf578cb84e7dec4d1add2afa60a3c7a1e041..d8802490b25cba65369f03d94627a2624f14b072 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -602,23 +602,13 @@ struct kvm_host_data { struct kvm_cpu_context host_ctxt; /* - * All pointers in this union are hyp VA. + * Hyp VA. * sve_state is only used in pKVM and if system_supports_sve(). */ - union { - struct user_fpsimd_state *fpsimd_state; - struct cpu_sve_state *sve_state; - }; - - union { - /* HYP VA pointer to the host storage for FPMR */ - u64 *fpmr_ptr; - /* - * Used by pKVM only, as it needs to provide storage - * for the host - */ - u64 fpmr; - }; + struct cpu_sve_state *sve_state; + + /* Used by pKVM only. */ + u64 fpmr; /* Ownership of the FP regs */ enum { diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index e6f0443210a8b7a65f616b25b2e6f74a05683ed6..634d3f62481827a3bf3aba6bf78cafed71b5bd32 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -2476,14 +2476,6 @@ static void finalize_init_hyp_mode(void) per_cpu_ptr_nvhe_sym(kvm_host_data, cpu)->sve_state = kern_hyp_va(sve_state); } - } else { - for_each_possible_cpu(cpu) { - struct user_fpsimd_state *fpsimd_state; - - fpsimd_state = &per_cpu_ptr_nvhe_sym(kvm_host_data, cpu)->host_ctxt.fp_regs; - per_cpu_ptr_nvhe_sym(kvm_host_data, cpu)->fpsimd_state = - kern_hyp_va(fpsimd_state); - } } } diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c index efb54ed60fe1d1d8a904b10a4a4bd3c820d9dac5..2ee6bde85235581d6bc9cba7e578c55875b5d5a1 100644 --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -64,8 +64,6 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) */ fpsimd_save_and_flush_cpu_state(); *host_data_ptr(fp_owner) = FP_STATE_FREE; - *host_data_ptr(fpsimd_state) = NULL; - *host_data_ptr(fpmr_ptr) = NULL; vcpu_clear_flag(vcpu, HOST_SVE_ENABLED); if (read_sysreg(cpacr_el1) & CPACR_EL1_ZEN_EL0EN) diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index 5310fe1da6165bcdedfb5ce61bce353e4c9dd58b..a7f6a653f33718d1a25e232608e63ea287f2a672 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -344,7 +344,28 @@ static inline void __hyp_sve_save_host(void) true); } -static void kvm_hyp_save_fpsimd_host(struct kvm_vcpu *vcpu); +static void kvm_hyp_save_fpsimd_host(struct kvm_vcpu *vcpu) +{ + /* + * Non-protected kvm relies on the host restoring its sve state. + * Protected kvm restores the host's sve state as not to reveal that + * fpsimd was used by a guest nor leak upper sve bits. + */ + if (system_supports_sve()) { + __hyp_sve_save_host(); + + /* Re-enable SVE traps if not supported for the guest vcpu. */ + if (!vcpu_has_sve(vcpu)) + cpacr_clear_set(CPACR_ELx_ZEN, 0); + + } else { + __fpsimd_save_state(host_data_ptr(host_ctxt.fp_regs)); + } + + if (kvm_has_fpmr(kern_hyp_va(vcpu->kvm))) + *host_data_ptr(fpmr) = read_sysreg_s(SYS_FPMR); +} + /* * We trap the first access to the FP/SIMD to save the host context and @@ -394,7 +415,7 @@ static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code) isb(); /* Write out the host state if it's in the registers */ - if (host_owns_fp_regs()) + if (is_protected_kvm_enabled() && host_owns_fp_regs()) kvm_hyp_save_fpsimd_host(vcpu); /* Restore the guest state */ diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index fefc89209f9e41c95478f6770881eb314a38b4c2..4e757a77322c9efc59cdff501745f7c80d452358 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -83,7 +83,7 @@ static void fpsimd_sve_sync(struct kvm_vcpu *vcpu) if (system_supports_sve()) __hyp_sve_restore_host(); else - __fpsimd_restore_state(*host_data_ptr(fpsimd_state)); + __fpsimd_restore_state(host_data_ptr(host_ctxt.fp_regs)); if (has_fpmr) write_sysreg_s(*host_data_ptr(fpmr), SYS_FPMR); diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c index 81d933a71310fd1132b2450cd08108e071a2cf78..3ce16f90fe6af7be21bc7b84a9d8b3905b8b08a7 100644 --- a/arch/arm64/kvm/hyp/nvhe/switch.c +++ b/arch/arm64/kvm/hyp/nvhe/switch.c @@ -193,34 +193,6 @@ static bool kvm_handle_pvm_sys64(struct kvm_vcpu *vcpu, u64 *exit_code) kvm_handle_pvm_sysreg(vcpu, exit_code)); } -static void kvm_hyp_save_fpsimd_host(struct kvm_vcpu *vcpu) -{ - /* - * Non-protected kvm relies on the host restoring its sve state. - * Protected kvm restores the host's sve state as not to reveal that - * fpsimd was used by a guest nor leak upper sve bits. - */ - if (unlikely(is_protected_kvm_enabled() && system_supports_sve())) { - __hyp_sve_save_host(); - - /* Re-enable SVE traps if not supported for the guest vcpu. */ - if (!vcpu_has_sve(vcpu)) - cpacr_clear_set(CPACR_ELx_ZEN, 0); - - } else { - __fpsimd_save_state(*host_data_ptr(fpsimd_state)); - } - - if (kvm_has_fpmr(kern_hyp_va(vcpu->kvm))) { - u64 val = read_sysreg_s(SYS_FPMR); - - if (unlikely(is_protected_kvm_enabled())) - *host_data_ptr(fpmr) = val; - else - **host_data_ptr(fpmr_ptr) = val; - } -} - static const exit_handler_fn hyp_exit_handlers[] = { [0 ... ESR_ELx_EC_MAX] = NULL, [ESR_ELx_EC_CP15_32] = kvm_hyp_handle_cp15_32, diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c index 80581b1c399595fd64d0ccada498edac322480a6..e7ca0424107adec2371ae4553ebab9857c60b6d9 100644 --- a/arch/arm64/kvm/hyp/vhe/switch.c +++ b/arch/arm64/kvm/hyp/vhe/switch.c @@ -309,14 +309,6 @@ static bool kvm_hyp_handle_eret(struct kvm_vcpu *vcpu, u64 *exit_code) return true; } -static void kvm_hyp_save_fpsimd_host(struct kvm_vcpu *vcpu) -{ - __fpsimd_save_state(*host_data_ptr(fpsimd_state)); - - if (kvm_has_fpmr(vcpu->kvm)) - **host_data_ptr(fpmr_ptr) = read_sysreg_s(SYS_FPMR); -} - static bool kvm_hyp_handle_tlbi_el2(struct kvm_vcpu *vcpu, u64 *exit_code) { int ret = -EINVAL;