From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-188.mta1.migadu.com (out-188.mta1.migadu.com [95.215.58.188]) (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 D2BB5768EC for ; Fri, 28 Jun 2024 21:18:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.188 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719609507; cv=none; b=DbY8+Ya0jjNzFKrUoM7BbXmQuqJQBDnvQNSPnppWp0HxkWp7y2RsjjiJ8J+/WFyCKWza2MhX1sDfwYYK62MGoZ+7E/dE4ryRGAUKPmya/5dxh23xHNZKoBwTgTR5jjGiuwawLCDFfCmlO6q64icr3qRmtgInr3NKPLUY5HjX51c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719609507; c=relaxed/simple; bh=BoFZDuqPzGP40r4KEUuGHvfn6bb2wtaddf0wdcA3lzM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=LTtTt90LG2UAnjZhJumtL4dKIh1HprsDetkciP8LmTxcDghQ5/C3o4+q27tKFceSvS7pEmQPKqm5fdp/m1SVhTCZ6q3mHnACM9qWF5UShVsd9P2t8SeZ8GA2vM8dmFTna7N2aXa2TBzHK3iguqaI6Fol8LggpVpCfbfvJWPzX0o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=YVmM27N0; arc=none smtp.client-ip=95.215.58.188 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="YVmM27N0" X-Envelope-To: sebastianene@google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1719609503; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=BLFP/6n6TmQFjaJH2t9PIEjVSqPuh54BsTLyCUC8RSI=; b=YVmM27N0679cDACz5KF6MA8iFPbbDxxnz/WCFjirVh5/zUhCa9y9hhyCJkhv0aHLRtdfOm Pp2Aa2N/di7yC62YGCgTIABkcS0wCBsjouiG9qaP9iPZjBuJcb3qFtzE0YogBYJLdcEAcA uV4dwgERknKjnetYQlbk1QX+YEVdoDo= X-Envelope-To: akpm@linux-foundation.org X-Envelope-To: alexghiti@rivosinc.com X-Envelope-To: ankita@nvidia.com X-Envelope-To: ardb@kernel.org X-Envelope-To: catalin.marinas@arm.com X-Envelope-To: christophe.leroy@csgroup.eu X-Envelope-To: james.morse@arm.com X-Envelope-To: vdonnefort@google.com X-Envelope-To: mark.rutland@arm.com X-Envelope-To: maz@kernel.org X-Envelope-To: rananta@google.com X-Envelope-To: ryan.roberts@arm.com X-Envelope-To: shahuang@redhat.com X-Envelope-To: suzuki.poulose@arm.com X-Envelope-To: will@kernel.org X-Envelope-To: yuzenghui@huawei.com X-Envelope-To: kvmarm@lists.linux.dev X-Envelope-To: linux-arm-kernel@lists.infradead.org X-Envelope-To: linux-kernel@vger.kernel.org X-Envelope-To: kernel-team@android.com Date: Fri, 28 Jun 2024 21:18:16 +0000 X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: Sebastian Ene Cc: akpm@linux-foundation.org, alexghiti@rivosinc.com, ankita@nvidia.com, ardb@kernel.org, catalin.marinas@arm.com, christophe.leroy@csgroup.eu, james.morse@arm.com, vdonnefort@google.com, mark.rutland@arm.com, maz@kernel.org, rananta@google.com, ryan.roberts@arm.com, shahuang@redhat.com, suzuki.poulose@arm.com, will@kernel.org, yuzenghui@huawei.com, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-team@android.com Subject: Re: [PATCH v7 5/6] KVM: arm64: Initialize the ptdump parser with stage-2 attributes Message-ID: References: <20240621123230.1085265-1-sebastianene@google.com> <20240621123230.1085265-6-sebastianene@google.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240621123230.1085265-6-sebastianene@google.com> X-Migadu-Flow: FLOW_OUT Hi Seb, On Fri, Jun 21, 2024 at 12:32:29PM +0000, Sebastian Ene wrote: > Define a set of attributes used by the ptdump parser to display the > properties of a guest memory region covered by a pagetable descriptor. > Build a description of the pagetable levels and initialize the parser > with this configuration. > > Signed-off-by: Sebastian Ene This patch should come *before* patch 4, no point in exposing the debugfs file if we aren't ready to handle it yet. > --- > arch/arm64/kvm/ptdump.c | 143 ++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 137 insertions(+), 6 deletions(-) > > diff --git a/arch/arm64/kvm/ptdump.c b/arch/arm64/kvm/ptdump.c > index 36dc7662729f..cc1d4fdddc6e 100644 > --- a/arch/arm64/kvm/ptdump.c > +++ b/arch/arm64/kvm/ptdump.c > @@ -14,6 +14,61 @@ > #include > > > +#define MARKERS_LEN (2) > +#define KVM_PGTABLE_MAX_LEVELS (KVM_PGTABLE_LAST_LEVEL + 1) > + > +struct kvm_ptdump_guest_state { > + struct kvm *kvm; > + struct pg_state parser_state; > + struct addr_marker ipa_marker[MARKERS_LEN]; > + struct pg_level level[KVM_PGTABLE_MAX_LEVELS]; > + struct ptdump_range range[MARKERS_LEN]; > +}; > + > +static const struct prot_bits stage2_pte_bits[] = { > + { > + .mask = PTE_VALID, > + .val = PTE_VALID, > + .set = " ", > + .clear = "F", > + }, { > + .mask = KVM_PTE_LEAF_ATTR_HI_S2_XN | PTE_VALID, > + .val = KVM_PTE_LEAF_ATTR_HI_S2_XN | PTE_VALID, > + .set = "XN", > + .clear = " ", > + }, { > + .mask = KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | PTE_VALID, > + .val = KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | PTE_VALID, > + .set = "R", > + .clear = " ", > + }, { > + .mask = KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | PTE_VALID, > + .val = KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | PTE_VALID, > + .set = "W", > + .clear = " ", > + }, { > + .mask = KVM_PTE_LEAF_ATTR_LO_S2_AF | PTE_VALID, > + .val = KVM_PTE_LEAF_ATTR_LO_S2_AF | PTE_VALID, > + .set = "AF", > + .clear = " ", > + }, { > + .mask = PTE_NG, > + .val = PTE_NG, > + .set = "FnXS", > + .clear = " ", > + }, { > + .mask = PTE_CONT | PTE_VALID, > + .val = PTE_CONT | PTE_VALID, > + .set = "CON", > + .clear = " ", > + }, { Neither of these bits are used at stage-2, why have descriptors for them? > +static int kvm_ptdump_build_levels(struct pg_level *level, u32 start_lvl) > +{ > + static const char * const level_names[] = {"PGD", "PUD", "PMD", "PTE"}; > + u32 i = 0; > + u64 mask = 0; > + > + if (start_lvl > 2) { > + pr_err("invalid start_lvl %u\n", start_lvl); > + return -EINVAL; > + } if (WARN_ON_ONCE(start_lvl >= KVM_PGTABLE_LAST_LEVEL)) return -EINVAL; > + for (i = 0; i < ARRAY_SIZE(stage2_pte_bits); i++) > + mask |= stage2_pte_bits[i].mask; > + > + for (i = start_lvl; i < KVM_PGTABLE_MAX_LEVELS; i++) { > + strscpy(level[i].name, level_names[i], sizeof(level[i].name)); > + > + level[i].num = ARRAY_SIZE(stage2_pte_bits); > + level[i].bits = stage2_pte_bits; > + level[i].mask = mask; > + } > + > + if (start_lvl > 0) > + strscpy(level[start_lvl].name, level_names[0], sizeof(level_names[0])); This should pass the size of @dst, not the source. This becomes slightly more self-documenting if you use a literal for "PGD" here too. strscpy(level[start_lvl].name, "PGD", sizeof(level[start_lvl].name)); > + return 0; > +} > + > +static struct kvm_ptdump_guest_state > +*kvm_ptdump_parser_init(struct kvm *kvm) > +{ > + struct kvm_ptdump_guest_state *st; > + struct kvm_s2_mmu *mmu = &kvm->arch.mmu; > + struct kvm_pgtable *pgtable = mmu->pgt; > + int ret; > + > + st = kzalloc(sizeof(struct kvm_ptdump_guest_state), GFP_KERNEL_ACCOUNT); > + if (!st) > + return NULL; > + > + ret = kvm_ptdump_build_levels(&st->level[0], pgtable->start_level); > + if (ret) > + goto free_with_state; I don't see any value in the use of goto here, as there isn't any sort of cascading initialization / cleanup. This also presents an opportunity to get an error back out to the caller. if (ret) { kfree(st); return ERR_PTR(ret); } > @@ -57,22 +176,34 @@ static int kvm_ptdump_guest_show(struct seq_file *m, void *unused) > static int kvm_ptdump_guest_open(struct inode *m, struct file *file) > { > struct kvm *kvm = m->i_private; > + struct kvm_ptdump_guest_state *st; > int ret; > > if (!kvm_get_kvm_safe(kvm)) > return -ENOENT; > > - ret = single_open(file, kvm_ptdump_guest_show, m->i_private); > - if (ret < 0) > - kvm_put_kvm(kvm); > + st = kvm_ptdump_parser_init(kvm); > + if (!st) { > + ret = -ENOMEM; > + goto free_with_kvm_ref; > + } (with the earlier suggestion) st = kvm_ptdump_parser_init(kvm); if (IS_ERR(st)) { ret = PTR_ERR(st); goto free_with_kvm_ref; } Otherwise genuine KVM bugs (-EINVAL) are getting lumped into ENOMEM. -- Thanks, Oliver