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 B413826B760 for ; Fri, 21 Nov 2025 17:40:39 +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=1763746839; cv=none; b=rp98wIfolcnlKiGaVPYWRZC804VZ/WPELZRqY6njSPqLTTLjOhqnoaf17LCZdquuQ2P2wywZ3kyXOwzyMbBc1iZ+w53BJDroMT4ktlCzvSo0J+WsHPNu2bwefFh3n9+X7i4+giiTkKTT98WkR0z8+c7Vd82mnJ6XbqPjlwK1B74= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763746839; c=relaxed/simple; bh=8nKZJhx3dG0Hpsj0XeH0juJ30gs8T8Bx7T+zCDpXYrI=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=OBaUPwluPLH9ZCQLANIRRfkdCwhQlNW7o0xEU1y/ZYJXxZ3Ao4vEqKYDFVOm8oG/P0tP4fmE93qHsh+maUaa7wHqXQ7b5dGO1xMxH+Z5EGt585WDGRcJZLYAUrlWfNFxklRlvIaGpZaeArIhncl69jDC8T6sqJWKgnXvIH18XgI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ueiJs/M/; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ueiJs/M/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 48187C4CEF1; Fri, 21 Nov 2025 17:40:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763746839; bh=8nKZJhx3dG0Hpsj0XeH0juJ30gs8T8Bx7T+zCDpXYrI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=ueiJs/M/Bfx20wpKI8HTyGkcEsphy7IlMjsBzHLeWFmIriuTAZQh2SVUuEYrZOYia 5GARj3h9RjEjMXL6fCy8CF9vqxqc9aMryVhbThbyc6GEuWHVQVxjv0Ia9HIJoa26nd EI7QqVfWa1SY/quoJ1Q69eJYiJhOnJsR2ZdRXyLbGR1MgZjqWPzvxFcvG2XsSeHF+Q EqpJOy7lXqw/BlraHIbejRkZ9iXqIKR6t68cEfQ8j9lj91lOZxNEy/tDVjKhxzxqmg Y3t8C9+RoHDQcy1GVmcQqmbWYh81LhZIhIxJ/U9xOvkoX6BYACoiniDGgCifBDQaXC yVWPWkrJirYCQ== Received: from sofa.misterjones.org ([185.219.108.64] helo=lobster-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1vMV7d-00000007JK2-0ol1; Fri, 21 Nov 2025 17:40:37 +0000 Date: Fri, 21 Nov 2025 17:40:36 +0000 Message-ID: <87see7ffmz.wl-maz@kernel.org> From: Marc Zyngier To: Oliver Upton Cc: kvmarm@lists.linux.dev, Joey Gouly , Suzuki K Poulose , Zenghui Yu Subject: Re: [PATCH v2 07/14] KVM: arm64: Handle endianness in read helper for emulated PTW In-Reply-To: <20251117224325.2431848-8-oupton@kernel.org> References: <20251117224325.2431848-1-oupton@kernel.org> <20251117224325.2431848-8-oupton@kernel.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: oupton@kernel.org, kvmarm@lists.linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Mon, 17 Nov 2025 22:43:18 +0000, Oliver Upton wrote: > > Implementing FEAT_HAFDBS means adding another descriptor accessor that > needs to deal with the guest-configured endianness. Prepare by moving > the endianness handling into the read accessor and out of the main body > of the S1/S2 PTWs. > > Signed-off-by: Oliver Upton > --- > arch/arm64/kvm/at.c | 25 +++++++++++++++++++------ > arch/arm64/kvm/nested.c | 30 +++++++++++++++++------------- > 2 files changed, 36 insertions(+), 19 deletions(-) > > diff --git a/arch/arm64/kvm/at.c b/arch/arm64/kvm/at.c > index be26d5aa668c..a295a37dd3b1 100644 > --- a/arch/arm64/kvm/at.c > +++ b/arch/arm64/kvm/at.c > @@ -362,6 +362,24 @@ static int setup_s1_walk(struct kvm_vcpu *vcpu, struct s1_walk_info *wi, > return -EFAULT; > } > > +static int kvm_read_s1_desc(struct kvm_vcpu *vcpu, u64 pa, u64 *desc, > + struct s1_walk_info *wi) > +{ > + u64 val; > + int r; > + > + r = kvm_read_guest(vcpu->kvm, pa, &val, sizeof(val)); > + if (r) > + return r; > + > + if (wi->be) > + *desc = be64_to_cpu((__force __be64)val); > + else > + *desc = le64_to_cpu((__force __le64)val); > + > + return 0; > +} > + > static int walk_s1(struct kvm_vcpu *vcpu, struct s1_walk_info *wi, > struct s1_walk_result *wr, u64 va) > { > @@ -414,17 +432,12 @@ static int walk_s1(struct kvm_vcpu *vcpu, struct s1_walk_info *wi, > return ret; > } > > - ret = kvm_read_guest(vcpu->kvm, ipa, &desc, sizeof(desc)); > + ret = kvm_read_s1_desc(vcpu, ipa, &desc, wi); > if (ret) { > fail_s1_walk(wr, ESR_ELx_FSC_SEA_TTW(level), false); > return ret; > } > > - if (wi->be) > - desc = be64_to_cpu((__force __be64)desc); > - else > - desc = le64_to_cpu((__force __le64)desc); > - > /* Invalid descriptor */ > if (!(desc & BIT(0))) > goto transfault; > diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c > index cf4b24e04a1a..10e68aab3d2a 100644 > --- a/arch/arm64/kvm/nested.c > +++ b/arch/arm64/kvm/nested.c > @@ -198,13 +198,26 @@ static int check_output_size(struct s2_walk_info *wi, phys_addr_t output) > return 0; > } > > -static int read_guest_s2_desc(phys_addr_t pa, u64 *desc, void *data) > +static int read_guest_s2_desc(phys_addr_t pa, u64 *desc, struct s2_walk_info *wi) > { > - struct kvm_vcpu *vcpu = data; > + struct kvm_vcpu *vcpu = wi->data; How about getting rid of this nonsense wi->data business? With the reader abstraction removed, this really serves no purpose. And aligning the read_guest_s[12]_desc() prototype. See below for an untested suggestion. Thanks, M. diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c index dbd3900e8bff6..e063061f21aad 100644 --- a/arch/arm64/kvm/nested.c +++ b/arch/arm64/kvm/nested.c @@ -124,7 +124,6 @@ int kvm_vcpu_init_nested(struct kvm_vcpu *vcpu) } struct s2_walk_info { - void *data; u64 baddr; unsigned int max_oa_bits; unsigned int pgshift; @@ -199,9 +198,9 @@ static int check_output_size(struct s2_walk_info *wi, phys_addr_t output) return 0; } -static int read_guest_s2_desc(phys_addr_t pa, u64 *desc, struct s2_walk_info *wi) +static int read_guest_s2_desc(struct kvm_vcpu *vcpu, + phys_addr_t pa, u64 *desc, struct s2_walk_info *wi) { - struct kvm_vcpu *vcpu = wi->data; u64 val; int r; @@ -221,11 +220,10 @@ static int read_guest_s2_desc(phys_addr_t pa, u64 *desc, struct s2_walk_info *wi return 0; } -static int swap_guest_s2_desc(phys_addr_t pa, u64 old, u64 new, +static int swap_guest_s2_desc(struct kvm_vcpu *vcpu, + phys_addr_t pa, u64 old, u64 new, struct s2_walk_info *wi) { - struct kvm_vcpu *vcpu = wi->data; - if (wi->be) { old = cpu_to_be64(old); new = cpu_to_be64(new); @@ -244,7 +242,7 @@ static int swap_guest_s2_desc(phys_addr_t pa, u64 old, u64 new, * * Must be called with the kvm->srcu read lock held */ -static int walk_nested_s2_pgd(phys_addr_t ipa, +static int walk_nested_s2_pgd(struct kvm_vcpu *vcpu, phys_addr_t ipa, struct s2_walk_info *wi, struct kvm_s2_trans *out) { int first_block_level, level, stride, input_size, base_lower_bound; @@ -295,7 +293,7 @@ static int walk_nested_s2_pgd(phys_addr_t ipa, >> (addr_bottom - 3); paddr = base_addr | index; - ret = read_guest_s2_desc(paddr, &desc, wi); + ret = read_guest_s2_desc(vcpu, paddr, &desc, wi); if (ret < 0) return ret; @@ -349,7 +347,7 @@ static int walk_nested_s2_pgd(phys_addr_t ipa, new_desc |= KVM_PTE_LEAF_ATTR_LO_S2_AF; if (new_desc != desc) { - ret = swap_guest_s2_desc(paddr, desc, new_desc, wi); + ret = swap_guest_s2_desc(vcpu, paddr, desc, new_desc, wi); if (ret) return ret; @@ -410,14 +408,13 @@ int kvm_walk_nested_s2(struct kvm_vcpu *vcpu, phys_addr_t gipa, if (!vcpu_has_nv(vcpu)) return 0; - wi.data = vcpu; wi.baddr = vcpu_read_sys_reg(vcpu, VTTBR_EL2); vtcr_to_walk_info(vtcr, &wi); wi.be = vcpu_read_sys_reg(vcpu, SCTLR_EL2) & SCTLR_ELx_EE; - ret = walk_nested_s2_pgd(gipa, &wi, result); + ret = walk_nested_s2_pgd(vcpu, gipa, &wi, result); if (ret) result->esr |= (kvm_vcpu_get_esr(vcpu) & ~ESR_ELx_FSC); -- Jazz isn't dead. It just smells funny.