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 1BC642F6191; Mon, 22 Dec 2025 14:37:16 +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=1766414237; cv=none; b=az9n4djOGuYJTkHfIjYASJ3OGOLsEN07EFuTNn9VAd/WnQqe3MdX6EEpoTP7Q8Oqz0MAY8fG50gFHymDtQTrFoDph9eCnGuVxDo7piS9rp1KvNo087VyHT2Tn8M+2a+5tQW+EYx2f+vUBzmaZjZPfg/fzmupSjb3Pm8YMrYyweQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766414237; c=relaxed/simple; bh=SZAm6zJ37Q2ZZv5+muaWfz5RqEM3fSD2IIVjceAvlJI=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=Y1wZ1vo1zpcHWrnMb/LK+t38lWrf+50ZVY9kRJBDsbMT2NmV1d8soHbkZOxq4R8e3PNPJWDkRbePuUVoAF7rZFOrY1q+DDH/W4zKg3HASE4q441M6esFi/eu2rWUj4VyHSc9ZSca7QWLL74KnHTExgAvlg4sVwMsmMkns+r9GTM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qt3TN6x8; 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="qt3TN6x8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BEBA2C4CEF1; Mon, 22 Dec 2025 14:37:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1766414236; bh=SZAm6zJ37Q2ZZv5+muaWfz5RqEM3fSD2IIVjceAvlJI=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=qt3TN6x8ZQV1g5ges+vWN1E5qT30zPvn5wSLwaVNCYv5CaE7v2scphPfC78SHmZFu mkzALcOFJ+V5rf78zsbkLicFTam0yM8lp2Abfub0UfvwwzH7Ss5WgxTLuUcWhQH9kG 9IOErza6afnba4FQdGMaJCnw7W9aqR/uiKioePYuJch5nigBFgCyLxkbNgCsRfB5G+ iw3add+Q8/oNt7xTRtK7MPlWTUqeZCHTE8eOdiYQFsHayBU22SrFaR2UIgNw8xEEkL nm5DYQjZfes261dUuMNO6bP8x75F1dCbBLv4mR1bqnweOD51HlIAh6a5PZ6zMrdOlg R2z/4AzU2TMWg== X-Mailer: emacs 30.2 (via feedmail 11-beta-1 I) From: Aneesh Kumar K.V To: Suzuki K Poulose , linux-kernel@vger.kernel.org, iommu@lists.linux.dev, linux-coco@lists.linux.dev Cc: Catalin Marinas , will@kernel.org, maz@kernel.org, tglx@linutronix.de, robin.murphy@arm.com, akpm@linux-foundation.org, jgg@ziepe.ca, steven.price@arm.com Subject: Re: [PATCH v2 3/4] coco: host: arm64: Handle hostconf RHI calls in kernel In-Reply-To: References: <20251221160920.297689-1-aneesh.kumar@kernel.org> <20251221160920.297689-4-aneesh.kumar@kernel.org> Date: Mon, 22 Dec 2025 20:07:06 +0530 Message-ID: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Suzuki K Poulose writes: > On 21/12/2025 16:09, Aneesh Kumar K.V (Arm) wrote: >> - Mark hostconf RHI SMC IDs as handled in the SMCCC filter. >> - Return version/features plus PAGE_SIZE alignment for guest queries. >> - Drop the 4K page-size guard in RMI init now that realm can query IPA >> change alignment size via the hostconf RHI >> >> Signed-off-by: Aneesh Kumar K.V (Arm) >> --- >> arch/arm64/kvm/hypercalls.c | 23 ++++++++++++++++++++++- >> arch/arm64/kvm/rmi.c | 4 ---- >> 2 files changed, 22 insertions(+), 5 deletions(-) >> >> diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c >> index 70ac7971416c..2861ca9063dd 100644 >> --- a/arch/arm64/kvm/hypercalls.c >> +++ b/arch/arm64/kvm/hypercalls.c >> @@ -8,6 +8,7 @@ >> >> #include >> #include >> +#include >> >> #define KVM_ARM_SMCCC_STD_FEATURES \ >> GENMASK(KVM_REG_ARM_STD_BMAP_BIT_COUNT - 1, 0) >> @@ -77,6 +78,9 @@ static bool kvm_smccc_default_allowed(u32 func_id) >> */ >> case ARM_SMCCC_VERSION_FUNC_ID: >> case ARM_SMCCC_ARCH_FEATURES_FUNC_ID: >> + case RHI_HOSTCONF_VERSION: >> + case RHI_HOSTCONF_FEATURES: >> + case RHI_HOSTCONF_GET_IPA_CHANGE_ALIGNMENT: >> return true; >> default: >> /* PSCI 0.2 and up is in the 0:0x1f range */ >> @@ -157,7 +161,15 @@ static int kvm_smccc_filter_insert_reserved(struct kvm *kvm) >> GFP_KERNEL_ACCOUNT); >> if (r) >> goto out_destroy; >> - >> + /* >> + * Don't forward RHI_HOST_CONF related RHI calls >> + */ >> + r = mtree_insert_range(&kvm->arch.smccc_filter, >> + RHI_HOSTCONF_VERSION, RHI_HOSTCONF_GET_IPA_CHANGE_ALIGNMENT, >> + xa_mk_value(KVM_SMCCC_FILTER_HANDLE), >> + GFP_KERNEL_ACCOUNT); > > minor nit: this is needed only for the Realms ? > That is the kvm forwarding of the RHI hostcalls to VMM. We are updating smccc filter that the SMCCC FID range [RHI_HOSTCONF_VERSION, RHI_HOSTCONF_GET_IPA_CHANGE_ALIGNMENT] will be handled by the kernel. This is needed because it is the kernel that is dropping the below check in kvm_init_rmi(). /* Only 4k page size on the host is supported */ if (PAGE_SIZE != SZ_4K) return; We want to make sure RHI support and dropping of the above check happens in the same patch and is part of the kernel. > >> + if (r) >> + goto out_destroy; >> return 0; >> out_destroy: >> mtree_destroy(&kvm->arch.smccc_filter); >> @@ -376,6 +388,15 @@ int kvm_smccc_call_handler(struct kvm_vcpu *vcpu) >> case ARM_SMCCC_TRNG_RND32: >> case ARM_SMCCC_TRNG_RND64: >> return kvm_trng_call(vcpu); >> + case RHI_HOSTCONF_VERSION: >> + val[0] = RHI_HOSTCONF_VER_1_0; >> + break; >> + case RHI_HOSTCONF_FEATURES: >> + val[0] = __RHI_HOSTCONF_GET_IPA_CHANGE_ALIGNMENT; >> + break; >> + case RHI_HOSTCONF_GET_IPA_CHANGE_ALIGNMENT: >> + val[0] = PAGE_SIZE; >> + break; >> default: >> return kvm_psci_call(vcpu); >> } >> diff --git a/arch/arm64/kvm/rmi.c b/arch/arm64/kvm/rmi.c >> index 9957a71d21b1..bd345e051a24 100644 >> --- a/arch/arm64/kvm/rmi.c >> +++ b/arch/arm64/kvm/rmi.c >> @@ -1935,10 +1935,6 @@ EXPORT_SYMBOL_GPL(kvm_has_da_feature); >> >> void kvm_init_rmi(void) >> { >> - /* Only 4k page size on the host is supported */ >> - if (PAGE_SIZE != SZ_4K) >> - return; > > For the record, these patches doesn't necessarily solve the Host support > fully. The KVM still needs to support splitting pages for RMM's 4K. > We already delegate RMM granules and setup stage 2 in rmm with RMM_PAGE_SIZE. ie, the shared patchset can be used to setup a 64K host with 4K Realm running on a RMM using 4K RMM granule size. > > That said, this can be ignored as we rebase the KVM to only support > RMM v2.0, where the Host can set the RMM's Stage2 page size. > > Suzuki > -aneesh