From patchwork Wed Apr 2 23:20:22 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 14036606 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 C1A18C3601A for ; Wed, 2 Apr 2025 23:49:03 +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=Qfc2Pi3v+Bb2gOAjnZ8Rj2WDjilYIvZCAJa0GQFdo30=; b=yvJjSpZP/fIlQk66YyDk1WFgI5 dkwqdtqBgINEjxnnh5NjmAW1IWcUlqp9n1/mnFNq9HEI2+KnDk06sTf071IX4pT2NmZhP0EEu1Nug +XYz84bKJ3jnA9CBY2k21onMYaZ2LUjfiZInKdcl/7JM08wVfye5ccBbkXvNC8cMWnvdU0RUmbh5m 0WVw+WmrL4hNZnw9HUxSOkCOud8E1r3me4MSzdsDu3Y9fz7Q271MffoILgDRgkmpXyx6FYwA8jcaP YUMGPQa4nAVWXuufCRTqL7slpXmhSE+P5pWENAxwZJhePxCKAgNlBH21X4Iqpy0wwqt8AEfO8OW/C A1+2Bvgg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.1 #2 (Red Hat Linux)) id 1u07pF-00000007Rl7-0VXH; Wed, 02 Apr 2025 23:48:53 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.98.1 #2 (Red Hat Linux)) id 1u07Od-00000007OLM-1ryG for linux-arm-kernel@lists.infradead.org; Wed, 02 Apr 2025 23:21:24 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 78AF64443A; Wed, 2 Apr 2025 23:21:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B8192C4CEDD; Wed, 2 Apr 2025 23:21:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743636082; bh=e9qvF2o7uVNtfQASnyy4CdQbnEmB3uPMMDe207tDMbc=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=d76twxCEnqhtukperv0HOO/yvbxwaRcOA33X0/ouHliMohTeCVWl7vc1J5hPVhSuu uXj7n2eKAduWaEPJ+CzqhP/PG2FHg50auU6xUpc2TvI7PY6/+HsSieVowFpd+OXoVY WhdIhZTFSs88gfm1S8FgfI5ElhsMxlyac6SiTMFTORvJlxTxddN12oVPVYqUogqvgH sWP/KrMf1mnT9FwblrSizykABl1QD4qp4lW7eN7nvdT2e8ip5pianzhN36RTbEIRFb 55OhmovD6m3wMO06Bw2mcHz29Mgd/eY3DHZmU1ivyRGY5SaY2Wnun8KUfaZNTjLcJ8 wMMT7UQTLsbFA== From: Mark Brown Date: Thu, 03 Apr 2025 00:20:22 +0100 Subject: [PATCH 5.15 v2 07/10] KVM: arm64: Remove host FPSIMD saving for non-protected KVM MIME-Version: 1.0 Message-Id: <20250403-stable-sve-5-15-v2-7-30a36a78a20a@kernel.org> References: <20250403-stable-sve-5-15-v2-0-30a36a78a20a@kernel.org> In-Reply-To: <20250403-stable-sve-5-15-v2-0-30a36a78a20a@kernel.org> To: Greg Kroah-Hartman , Marc Zyngier , James Morse , Suzuki K Poulose , Catalin Marinas , Will Deacon , Oleg Nesterov , Oliver Upton Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Mark Brown , Mark Rutland , Fuad Tabba X-Mailer: b4 0.15-dev-c25d1 X-Developer-Signature: v=1; a=openpgp-sha256; l=2943; i=broonie@kernel.org; h=from:subject:message-id; bh=IYSm9LOHiakFHli8QpJhz4RyCAaedNNXODj93c0ElHY=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBn7cZRAiw8fTObijRUYHvuAUQ8JqfR9J23+Sw7pEnA 6Y43d+aJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZ+3GUQAKCRAk1otyXVSH0MB+B/ wJ4puNvT47y3n3mvZUN9xNBPAL8/XtQpcTXrAHfZfMEEtdqCYHJdZUCkGRmt3PUU/Ic/KC5jQqN/5k SaxQrxRBAkBn4hvEA/3BoSjbqqA6Mur4G8H8mtQdXd60twTL8lUtWarXUdLrj3Jy+wRoGq8sORdCpF pvSusjb9EuuDbu3a4HtU8gtW1QFAhOR4jgeS+qivFoa/DPMbctIPu17WdjzJyOcrG3qW+2WyXdpdkv jDUDHDKTgqHA4+4121g1Rqo89zO3AUfhipoyG4+3WMZkL33/lbLs2PV0DBSJHOwynSPV/C3tAGXygw Yjvq0+mtwtmcWv+I6Rd7ndyFNfltdZ 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-20250402_162123_518408_E7392011 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: Mark Rutland [ Upstream commit 8eca7f6d5100b6997df4f532090bc3f7e0203bef ] 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 | 1 - arch/arm64/kvm/fpsimd.c | 1 - arch/arm64/kvm/hyp/include/hyp/switch.h | 6 +----- 3 files changed, 1 insertion(+), 7 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index ecae31b0dab3..06e8d4645ecd 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -333,7 +333,6 @@ struct kvm_vcpu_arch { struct kvm_guest_debug_arch external_debug_state; struct thread_info *host_thread_info; /* hyp VA */ - struct user_fpsimd_state *host_fpsimd_state; /* hyp VA */ struct { /* {Break,watch}point registers */ diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c index 2afa2521bce1..1ef9d6cb91ee 100644 --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -55,7 +55,6 @@ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu) } vcpu->arch.host_thread_info = kern_hyp_va(ti); - vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd); error: return ret; } diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index 269ec3587210..cc102e46b0e2 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -251,11 +251,7 @@ static inline bool __hyp_handle_fpsimd(struct kvm_vcpu *vcpu) } isb(); - if (vcpu->arch.flags & KVM_ARM64_FP_HOST) { - __fpsimd_save_state(vcpu->arch.host_fpsimd_state); - vcpu->arch.flags &= ~KVM_ARM64_FP_HOST; - } - + /* Restore the guest state */ if (sve_guest) __hyp_sve_restore_guest(vcpu); else