From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 151883148A3; Fri, 20 Mar 2026 16:41:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774024881; cv=none; b=DgDFEjRv1jTNBOBa8YngB9tRz+zrEZ+/I6k8zpuBQFRJn2FZotISETw+iVX2I2W42nnld487Gqg6hFM9USMqfJJVbZY6yWGEWBy80/bSDdr9DROAOKBy7+XREEbtqxEjxqvafV4krarIZgkzhAj5KQPHHXJAtU7EetfQKNgEdIU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774024881; c=relaxed/simple; bh=zUNtSO0oHm5MDL+J4wuWFAaiJoGUV89YPzQp5WYIpnY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=RP9Ar8N0BJByapBTAjBjjO7zftlHVKMLQczyu8dsxnvZ+1mGHBlL/d4vth3RKmNsBiRc0RLm6aJMUo56qnJOnCUmtwqUpMP877nSzPq0BF6I2HrMf9oyOa5vG1YYiKJWnA3H9E3IRRI+xAorK1jDQJi3Cf7al6ALEXMRAfCmqxY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 782A8165C; Fri, 20 Mar 2026 09:41:13 -0700 (PDT) Received: from [10.1.29.20] (e122027.cambridge.arm.com [10.1.29.20]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 148A53F7BD; Fri, 20 Mar 2026 09:41:14 -0700 (PDT) Message-ID: Date: Fri, 20 Mar 2026 16:41:12 +0000 Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v13 26/48] arm64: RMI: Create the realm descriptor To: Wei-Lin Chang , kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: Catalin Marinas , Marc Zyngier , Will Deacon , James Morse , Oliver Upton , Suzuki K Poulose , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Alexandru Elisei , Christoffer Dall , Fuad Tabba , linux-coco@lists.linux.dev, Ganapatrao Kulkarni , Gavin Shan , Shanker Donthineni , Alper Gun , "Aneesh Kumar K . V" , Emi Kisanuki , Vishal Annapurve References: <20260318155413.793430-1-steven.price@arm.com> <20260318155413.793430-27-steven.price@arm.com> From: Steven Price Content-Language: en-GB In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 19/03/2026 18:25, Wei-Lin Chang wrote: > On Wed, Mar 18, 2026 at 03:53:50PM +0000, Steven Price wrote: >> Creating a realm involves first creating a realm descriptor (RD). This >> involves passing the configuration information to the RMM. Do this as >> part of realm_ensure_created() so that the realm is created when it is >> first needed. >> >> Signed-off-by: Steven Price >> --- >> Changes since v12: >> * Since RMM page size is now equal to the host's page size various >> calculations are simplified. >> * Switch to using range based APIs to delegate/undelegate. >> * VMID handling is now handled entirely by the RMM. >> --- >> arch/arm64/kvm/rmi.c | 94 +++++++++++++++++++++++++++++++++++++++++++- >> 1 file changed, 92 insertions(+), 2 deletions(-) >> >> diff --git a/arch/arm64/kvm/rmi.c b/arch/arm64/kvm/rmi.c >> index 38349c7b34f4..d5fee203824b 100644 >> --- a/arch/arm64/kvm/rmi.c >> +++ b/arch/arm64/kvm/rmi.c >> @@ -649,6 +649,83 @@ static void realm_unmap_shared_range(struct kvm *kvm, >> start, end); >> } >> >> +static int realm_create_rd(struct kvm *kvm) >> +{ >> + struct realm *realm = &kvm->arch.realm; >> + struct realm_params *params = realm->params; >> + void *rd = NULL; >> + phys_addr_t rd_phys, params_phys; >> + size_t pgd_size = kvm_pgtable_stage2_pgd_size(kvm->arch.mmu.vtcr); >> + int i, r; >> + >> + realm->ia_bits = VTCR_EL2_IPA(kvm->arch.mmu.vtcr); >> + >> + if (WARN_ON(realm->rd || !realm->params)) >> + return -EEXIST; >> + >> + rd = (void *)__get_free_page(GFP_KERNEL); > > Hi, > > Should this be GFP_KERNEL_ACCOUNT? Yes that would be better. >> + if (!rd) >> + return -ENOMEM; >> + >> + rd_phys = virt_to_phys(rd); >> + if (delegate_page(rd_phys)) { >> + r = -ENXIO; >> + goto free_rd; >> + } >> + >> + if (delegate_range(kvm->arch.mmu.pgd_phys, pgd_size)) { >> + r = -ENXIO; >> + goto out_undelegate_tables; >> + } >> + >> + params->s2sz = VTCR_EL2_IPA(kvm->arch.mmu.vtcr); >> + params->rtt_level_start = get_start_level(realm); >> + params->rtt_num_start = pgd_size / PAGE_SIZE; >> + params->rtt_base = kvm->arch.mmu.pgd_phys; >> + >> + if (kvm->arch.arm_pmu) { >> + params->pmu_num_ctrs = kvm->arch.nr_pmu_counters; >> + params->flags |= RMI_REALM_PARAM_FLAG_PMU; >> + } >> + >> + if (kvm_lpa2_is_enabled()) >> + params->flags |= RMI_REALM_PARAM_FLAG_LPA2; >> + >> + params_phys = virt_to_phys(params); >> + >> + if (rmi_realm_create(rd_phys, params_phys)) { >> + r = -ENXIO; >> + goto out_undelegate_tables; >> + } >> + >> + if (WARN_ON(rmi_rec_aux_count(rd_phys, &realm->num_aux))) { >> + WARN_ON(rmi_realm_destroy(rd_phys)); >> + r = -ENXIO; >> + goto out_undelegate_tables; >> + } >> + >> + realm->rd = rd; >> + WRITE_ONCE(realm->state, REALM_STATE_NEW); >> + /* The realm is up, free the parameters. */ >> + free_page((unsigned long)realm->params); >> + realm->params = NULL; >> + >> + return 0; >> + >> +out_undelegate_tables: >> + if (WARN_ON(undelegate_range(kvm->arch.mmu.pgd_phys, i))) { >> + /* Leak the pages if they cannot be returned */ >> + kvm->arch.mmu.pgt = NULL; > > Did you mean kvm->arch.mmu.pgd_phys = NULL; ? No, although I agree this isn't exactly ideal. kvm_free_stage2_pgd() uses mmu->pgt to decide whether to free the memory - pgd_phys isn't used in that path. Technically here we end up leaking more than just the PGD pages in this case, but as it's a "should never happen" case I didn't see the need to worry about the leak being a bit larger than necessary. Thanks, Steve > Thanks, > Wei-Lin Chang > >> + } >> + if (WARN_ON(undelegate_page(rd_phys))) { >> + /* Leak the page if it isn't returned */ >> + return r; >> + } >> +free_rd: >> + free_page((unsigned long)rd); >> + return r; >> +} >> + >> static void realm_unmap_private_range(struct kvm *kvm, >> unsigned long start, >> unsigned long end, >> @@ -893,8 +970,21 @@ static int realm_init_ipa_state(struct kvm *kvm, >> >> static int realm_ensure_created(struct kvm *kvm) >> { >> - /* Provided in later patch */ >> - return -ENXIO; >> + int ret; >> + >> + switch (kvm_realm_state(kvm)) { >> + case REALM_STATE_NONE: >> + break; >> + case REALM_STATE_NEW: >> + return 0; >> + case REALM_STATE_DEAD: >> + return -ENXIO; >> + default: >> + return -EBUSY; >> + } >> + >> + ret = realm_create_rd(kvm); >> + return ret; >> } >> >> static int set_ripas_of_protected_regions(struct kvm *kvm) >> -- >> 2.43.0 >>