From mboxrd@z Thu Jan 1 00:00:00 1970 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 47B2126FD95; Tue, 25 Mar 2025 12:40:15 +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=1742906415; cv=none; b=DZaiMPKAhtPHDnRRNqaqGSlfQs3rsee3KFx2OntP1ghleHpSsFsfRABRlvx1B2NEpbNsSX2FCA9FB+HR0E9KcXKJ6wDqsH7+Ku30s+CicsODgeFpRyH1c7X73YylwbciC11lhJjvf/RlncaxRvhenq0yjLBm+VLHUQN+XfrYe3Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742906415; c=relaxed/simple; bh=kX+ibNaHopNDzKeCftVlurr7ZCAmD47Vgr1XNzphKi0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qxj3Ebt1F2xC+WZpGpHpu7hszctzQ/euX+MSCWnR5F+/4vjKMPSaUv2WwzslUtYiaE59Q3uz2rGTdDRtc4QPtJI5S3u5Kxj2jUfdI5d9peavilVbHPBL2+YM8msykB2olBVKbneQtGqlwGWD+4G1DGIy0JSQDNYGJYGc2fbBcNI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=XA0IBWCc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="XA0IBWCc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D4A45C4CEE4; Tue, 25 Mar 2025 12:40:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1742906415; bh=kX+ibNaHopNDzKeCftVlurr7ZCAmD47Vgr1XNzphKi0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XA0IBWCcwt3IUIQmIbzaLreJMP6cgD/IDbSpEsESNeEQipID9BAO/ARyruhZJQKaf 7YSnvgbyYuM3ACI74Mhj7u7MWlfOJdFUMudWdOlTJ1TkklfMDqHuJxYzN7scLiLheV RDVgLaLR9rkb6C5wQEwkwKL2jlmEojbhDSGo0G3M= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mark Rutland , Mark Brown , Will Deacon , Catalin Marinas , Fuad Tabba , Marc Zyngier , Oliver Upton Subject: [PATCH 6.12 106/116] KVM: arm64: Remove host FPSIMD saving for non-protected KVM Date: Tue, 25 Mar 2025 08:23:13 -0400 Message-ID: <20250325122151.917068488@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250325122149.207086105@linuxfoundation.org> References: <20250325122149.207086105@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ 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 Signed-off-by: Greg Kroah-Hartman --- arch/arm64/include/asm/kvm_host.h | 18 ++++-------------- 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, 28 insertions(+), 63 deletions(-) --- 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; - }; + 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; - }; + /* Used by pKVM only. */ + u64 fpmr; /* Ownership of the FP regs */ enum { --- 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); - } } } --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -64,8 +64,6 @@ void kvm_arch_vcpu_load_fp(struct kvm_vc */ 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) --- 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(v 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 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 */ --- 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_v 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); --- 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_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, --- 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 k 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;