From patchwork Fri Apr 4 13:23:39 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 14038492 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 5B135C36010 for ; Fri, 4 Apr 2025 13:39:59 +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=i8cR9zwHtfrGwAZzZvi07Fb5vpqwnNfXNFjt+wO/qS0=; b=cvsOQ134ojpmpcaMF/XaR9U4DM PQjAV3hcmGQyUrDsOkIX6UXHLdCtP1i6JQiD9bTHXQucPjdvEicH9WSSO4frqbAaXHoMcRtXazIdH HVU6aT3ZVf/+eFJaPfmo69DZhxMyu25okL64mmjv5AuJIvOfr0Tny0sVGmSnJcIMQHlltPKZN1sBx 8636KwS7ZNIrFokjsrBI2L9ssUJyBIU83PMCXvV1pEbJDrxdiKSX4QxhcIx8cJeJSN4+vVTK/6fm1 +gAfJkSUCWkulyKIJlC8If5lJdN23+aBnMzS1oZCU2HITCXO0M0Bb805Df/Ndfu3qobrWrINT6trx caOgMi5Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.1 #2 (Red Hat Linux)) id 1u0hGv-0000000BrHz-2umu; Fri, 04 Apr 2025 13:39:49 +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 1u0h5I-0000000BpAh-1bBQ for linux-arm-kernel@lists.infradead.org; Fri, 04 Apr 2025 13:27:49 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 9494945063; Fri, 4 Apr 2025 13:27:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0FC9BC4CEDD; Fri, 4 Apr 2025 13:27:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743773268; bh=hbSvXiBm9+ecDREEoF8K9gTlgChPGoVUykMZmaDm+6o=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=PTJUHtQgiGAVjWZVpHELgRO9Y4YrwfoUmAp2LmJIckrB0H+DP8Uvktuv/kG3rixHg ggHHsYVZpPXo6jJPZQ2lwGyJE7ehQsrhsy/g3r6h1dpVXckr359ikSnEWilL9ZND0Q r7f68x7Y1aX6rXOr7uZ8J4+f9HzSMrl/7MV24G9vB7vKsqw9Gej0EIHc09YPdAS1dN g2N+U6BzMEEyGagyDfoS8FYQF1irwu11c1/9PGWrPHmD9q9AAUIGmeiW8+KNmTds8C Y6vhbfwTLFGU5oBVJ+OyW7O78ic7f54mgd5ybz/bT2KysNYyZjSJGCA7VUyUZ3wsZF tUzZK+4yIER+A== From: Mark Brown Date: Fri, 04 Apr 2025 14:23:39 +0100 Subject: [PATCH RESEND 6.1 06/12] KVM: arm64: Remove host FPSIMD saving for non-protected KVM MIME-Version: 1.0 Message-Id: <20250404-stable-sve-6-1-v1-6-cd5c9eb52d49@kernel.org> References: <20250404-stable-sve-6-1-v1-0-cd5c9eb52d49@kernel.org> In-Reply-To: <20250404-stable-sve-6-1-v1-0-cd5c9eb52d49@kernel.org> To: Catalin Marinas , Will Deacon , Marc Zyngier , James Morse , Suzuki K Poulose , Oliver Upton , Oleg Nesterov , Greg Kroah-Hartman Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, kvmarm@lists.cs.columbia.edu, Mark Brown , stable@vger.kernel.org, Mark Rutland , Fuad Tabba X-Mailer: b4 0.15-dev-c25d1 X-Developer-Signature: v=1; a=openpgp-sha256; l=3037; i=broonie@kernel.org; h=from:subject:message-id; bh=uTm4PvNAnNOKeIcBzhUY58bCxrtjcjA28blOXgiiseU=; b=owGbwMvMwMWocq27KDak/QLjabUkhvT39wxtFU6Fmt71K12zwlJNWu9wwpRw7511af2Kp68tWe6z 0T6lk9GYhYGRi0FWTJFl7bOMVenhElvnP5r/CmYQKxPIFAYuTgGYyA9t9n8GW8LedOokhfrPPcR8Ki yHL69OyfLe3DmW78MuLldaoVNhXaKxOeurVeCpaK113eutDzxLTjrpYOKzWYujPeC7aME8f93+WrPt 5vxCZXdLuKPTWiT/XKrbr7bTOKlLTWKDXoe46sQffzpv/ws5vdz3h/K/jWe2yAQfMIh6uoZH8ZjWLg HJl4yqeU/cT/cHPo7/kC+ufsHn4fX1GqnSFxjsDHmKPO48dQ5YVxn/wmJCA2vLqYfftnXtLIw786jo 0YfKngMP+oJy7st16mSV+CQs7Ao46Xek0jGs/kDWJL2arn/tAp098lZv+Pcn77xZs7ZnT/GcKM1PP1 9E+4jO2dLdUhU26Y3WHQmJTwLOAA== 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-20250404_062748_465025_5DC86CDA X-CRM114-Status: GOOD ( 16.93 ) 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 | 2 -- arch/arm64/kvm/hyp/include/hyp/switch.h | 4 ---- 3 files changed, 7 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 0e9b093adc67..7f187ac24e5d 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -380,7 +380,6 @@ struct kvm_vcpu_arch { struct kvm_guest_debug_arch vcpu_debug_state; struct kvm_guest_debug_arch external_debug_state; - struct user_fpsimd_state *host_fpsimd_state; /* hyp VA */ struct task_struct *parent_task; struct { diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c index 1765f723afd4..ee7c59f96451 100644 --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -49,8 +49,6 @@ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu) if (ret) return ret; - vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd); - /* * We need to keep current's task_struct pinned until its data has been * unshared with the hypervisor to make sure it is not re-used by the diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index 081aca8f432e..50e6f3fcc27c 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -207,10 +207,6 @@ 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 (vcpu->arch.fp_state == FP_STATE_HOST_OWNED) - __fpsimd_save_state(vcpu->arch.host_fpsimd_state); - /* Restore the guest state */ if (sve_guest) __hyp_sve_restore_guest(vcpu);