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 23FBC271468; Fri, 19 Jun 2026 00:31:49 +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=1781829109; cv=none; b=MJU+3d2HbLo7awScswiHg9J5NNG3ZkCmwheZtjGQexeBJcjBZaUccKfBVPG3CNUxf9hwJ/Lw/PU6LabCY2d4hwUnKYITM1frFYDMqzW3ZlBn72HIRqaRdKey8SL5555d0J/5m8zB0Svq71zhIAFwvunQzMhr1necKFVZg2gplGw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781829109; c=relaxed/simple; bh=Y214D8EYmmgv568dSI8IvVw1cEvRPeVuqU4a72w++2A=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=SDAzGd76eYn/FGmx1nLiRY3kwVHTdhmwYECoCQVHSKUnsOdG9SmNQ05O6hiHzMLMkbjvv/5lz/UNE+Qse1B22eDB8zrRDW3Em3DuFgw1jJII9l0nxCpzTFiNyZJLVdvvSPZyOb2H1GPSD5+SWjPi35BVVBjAepdawez1Jpga67A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NlF2jgAE; 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="NlF2jgAE" Received: by smtp.kernel.org (Postfix) with ESMTPS id 04FF2C2BCC6; Fri, 19 Jun 2026 00:31:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1781829109; bh=Y214D8EYmmgv568dSI8IvVw1cEvRPeVuqU4a72w++2A=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=NlF2jgAEgLXc32TObuwkFWM6FDc/MRDYtPW3Pdje7AtJ7TMv2xfqzEfj0C8N5UJoY ADvhT2NwZ8bRX2k7Y0CU20PNOxpk2TvopxfN4F8UkgCo4D8YcGZI7sSKIOtrhLLvbl hoDp4kFb/jLnpCS3OoRv5A90K7GUQlGgcWUwDb81I/zz98U3tUWcsSbjOzpoPiZ4vU tH57XhPE1VSrZLb8FjchEG5AzwapOZwjv7+84kDhqRNb5oDi5Emi8pXdbuhdJgHz5h wywsOJdL0kySadWdHzQp2Ar78B4Xhkz5xQjtvX8fRFqXlwNEurC1BW0BQEc+5OdMjT 599aDvLRN8r4A== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id EF939CD98FA; Fri, 19 Jun 2026 00:31:48 +0000 (UTC) From: Ackerley Tng via B4 Relay Date: Thu, 18 Jun 2026 17:31:59 -0700 Subject: [PATCH v8 22/46] KVM: SEV: Make 'uaddr' parameter optional for KVM_SEV_SNP_LAUNCH_UPDATE Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260618-gmem-inplace-conversion-v8-22-9d2959357853@google.com> References: <20260618-gmem-inplace-conversion-v8-0-9d2959357853@google.com> In-Reply-To: <20260618-gmem-inplace-conversion-v8-0-9d2959357853@google.com> To: aik@amd.com, andrew.jones@linux.dev, binbin.wu@linux.intel.com, brauner@kernel.org, chao.p.peng@linux.intel.com, david@kernel.org, jmattson@google.com, jthoughton@google.com, michael.roth@amd.com, oupton@kernel.org, pankaj.gupta@amd.com, qperret@google.com, rick.p.edgecombe@intel.com, rientjes@google.com, shivankg@amd.com, steven.price@arm.com, tabba@google.com, willy@infradead.org, wyihan@google.com, yan.y.zhao@intel.com, forkloop@google.com, pratyush@kernel.org, suzuki.poulose@arm.com, aneesh.kumar@kernel.org, liam@infradead.org, Paolo Bonzini , Sean Christopherson , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Jonathan Corbet , Shuah Khan , Shuah Khan , Vishal Annapurve , Andrew Morton , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Youngjun Park , Qi Zheng , Shakeel Butt , Kiryl Shutsemau , Baoquan He , Jason Gunthorpe , Vlastimil Babka , Baoquan He Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev, Ackerley Tng X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1781829104; l=5933; i=ackerleytng@google.com; s=20260225; h=from:subject:message-id; bh=tQi8qJkknAfBcTf104klaFd67JuBPmTFwmizL4oPy4s=; b=cBnNnoLB2QhAJ01EMqCMeHMFVTh1iL/r71OEPnr9gP+uhJkS5miQxdNfBwmLFGOyrFudZ3yq8 UKBdIrAZ5GoBQvjOaWCtl+Vff7GXA2/xXhyee4hOFCtbxfJHXEGcS+L X-Developer-Key: i=ackerleytng@google.com; a=ed25519; pk=sAZDYXdm6Iz8FHitpHeFlCMXwabodTm7p8/3/8xUxuU= X-Endpoint-Received: by B4 Relay for ackerleytng@google.com/20260225 with auth_id=649 X-Original-From: Ackerley Tng Reply-To: ackerleytng@google.com From: Michael Roth Make the source page for populating an SNP guest_memfd instance optional if in-place conversion/population is enabled. If KVM can convert the page in-place, then it's possible for guest memory to be initialized directly from userspace by mmap()'ing the guest_memfd and writing to it while the corresponding GPA ranges are in a 'shared' state, before converting them to the 'private' state expected by KVM_SEV_SNP_LAUNCH_UPDATE. Update the handling/documentation for KVM_SEV_SNP_LAUNCH_UPDATE to allow for 'uaddr' to be set to NULL when in-place conversion is enabled, which SNP_LAUNCH_UPDATE will then use to determine when it should/shouldn't copy in data from a separate memory location. Continue to enforce non-NULL when PRIVATE is tracked per-VM, not per-guest_memfd. Signed-off-by: Michael Roth [Added src_page check in error handling path when the firmware command fails] [Dropped ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES] Signed-off-by: Ackerley Tng [sean: drop explicit vm_memory_attributes references] Signed-off-by: Sean Christopherson --- Documentation/virt/kvm/x86/amd-memory-encryption.rst | 13 +++++++++---- arch/x86/kvm/svm/sev.c | 16 +++++++++++----- virt/kvm/kvm_main.c | 1 + 3 files changed, 21 insertions(+), 9 deletions(-) diff --git a/Documentation/virt/kvm/x86/amd-memory-encryption.rst b/Documentation/virt/kvm/x86/amd-memory-encryption.rst index bd04a908a8dbd..29409297f1ef0 100644 --- a/Documentation/virt/kvm/x86/amd-memory-encryption.rst +++ b/Documentation/virt/kvm/x86/amd-memory-encryption.rst @@ -503,7 +503,8 @@ secrets. It is required that the GPA ranges initialized by this command have had the KVM_MEMORY_ATTRIBUTE_PRIVATE attribute set in advance. See the documentation -for KVM_SET_MEMORY_ATTRIBUTES for more details on this aspect. +for KVM_SET_MEMORY_ATTRIBUTES/KVM_SET_MEMORY_ATTRIBUTES2 for more details on +this aspect. Upon success, this command is not guaranteed to have processed the entire range requested. Instead, the ``gfn_start``, ``uaddr``, and ``len`` fields of @@ -511,9 +512,13 @@ range requested. Instead, the ``gfn_start``, ``uaddr``, and ``len`` fields of remaining range that has yet to be processed. The caller should continue calling this command until those fields indicate the entire range has been processed, e.g. ``len`` is 0, ``gfn_start`` is equal to the last GFN in the -range plus 1, and ``uaddr`` is the last byte of the userspace-provided source -buffer address plus 1. In the case where ``type`` is KVM_SEV_SNP_PAGE_TYPE_ZERO, -``uaddr`` will be ignored completely. +range plus 1, and ``uaddr`` (if specified) is the last byte of the +userspace-provided source buffer address plus 1. + +In the case where ``type`` is KVM_SEV_SNP_PAGE_TYPE_ZERO, ``uaddr`` will be +ignored completely. For all other page types, ``uaddr`` is optional if in-place +conversion is enable, i.e. when the destination can also be the source, and is +required if in-place conversion is disabled. Parameters (in): struct kvm_sev_snp_launch_update diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 74fb15551e83f..2b7569b6a8609 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -2330,7 +2330,13 @@ static int sev_gmem_post_populate(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int level; int ret; - if (WARN_ON_ONCE(sev_populate_args->type != KVM_SEV_SNP_PAGE_TYPE_ZERO && !src_page)) + /* + * A source page is required if in-place conversion isn't enabled, as + * the data needs to come from a separate physical page. Zero pages + * are exempt as they don't consume a source page. + */ + if (!gmem_in_place_conversion && + sev_populate_args->type != KVM_SEV_SNP_PAGE_TYPE_ZERO && !src_page) return -EINVAL; ret = snp_lookup_rmpentry((u64)pfn, &assigned, &level); @@ -2377,7 +2383,7 @@ static int sev_gmem_post_populate(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, */ if (ret && !snp_page_reclaim(kvm, pfn) && sev_populate_args->type == KVM_SEV_SNP_PAGE_TYPE_CPUID && - sev_populate_args->fw_error == SEV_RET_INVALID_PARAM) { + sev_populate_args->fw_error == SEV_RET_INVALID_PARAM && src_page) { void *src_vaddr = kmap_local_page(src_page); void *dst_vaddr = kmap_local_pfn(pfn); @@ -2410,8 +2416,8 @@ static int snp_launch_update(struct kvm *kvm, struct kvm_sev_cmd *argp) if (copy_from_user(¶ms, u64_to_user_ptr(argp->data), sizeof(params))) return -EFAULT; - pr_debug("%s: GFN start 0x%llx length 0x%llx type %d flags %d\n", __func__, - params.gfn_start, params.len, params.type, params.flags); + pr_debug("%s: GFN start 0x%llx length 0x%llx type %d flags %d src %llx\n", __func__, + params.gfn_start, params.len, params.type, params.flags, params.uaddr); if (!params.len || !PAGE_ALIGNED(params.len) || params.flags || (params.type != KVM_SEV_SNP_PAGE_TYPE_NORMAL && @@ -2468,7 +2474,7 @@ static int snp_launch_update(struct kvm *kvm, struct kvm_sev_cmd *argp) params.gfn_start += count; params.len -= count * PAGE_SIZE; - if (params.type != KVM_SEV_SNP_PAGE_TYPE_ZERO) + if (src && params.type != KVM_SEV_SNP_PAGE_TYPE_ZERO) params.uaddr += count * PAGE_SIZE; if (copy_to_user(u64_to_user_ptr(argp->data), ¶ms, sizeof(params))) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 044486f128c37..dd1d18a1d2f68 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -103,6 +103,7 @@ module_param(allow_unsafe_mappings, bool, 0444); #ifdef kvm_arch_has_private_mem bool __ro_after_init gmem_in_place_conversion = false; +EXPORT_SYMBOL_FOR_KVM_INTERNAL(gmem_in_place_conversion); #endif #define MEMORY_ATTRIBUTES_MATCH(one, two) \ -- 2.55.0.rc0.738.g0c8ab3ebcc-goog