linux/drivers/virt, branch v6.7

Merge tag 'tsm-for-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/linux

2023-11-05T01:58:13Z

Pull unified attestation reporting from Dan Williams: "In an ideal world there would be a cross-vendor standard attestation report format for confidential guests along with a common device definition to act as the transport. In the real world the situation ended up with multiple platform vendors inventing their own attestation report formats with the SEV-SNP implementation being a first mover to define a custom sev-guest character device and corresponding ioctl(). Later, this configfs-tsm proposal intercepted an attempt to add a tdx-guest character device and a corresponding new ioctl(). It also anticipated ARM and RISC-V showing up with more chardevs and more ioctls(). The proposal takes for granted that Linux tolerates the vendor report format differentiation until a standard arrives. From talking with folks involved, it sounds like that standardization work is unlikely to resolve anytime soon. It also takes the position that kernfs ABIs are easier to maintain than ioctl(). The result is a shared configfs mechanism to return per-vendor report-blobs with the option to later support a standard when that arrives. Part of the goal here also is to get the community into the "uncomfortable, but beneficial to the long term maintainability of the kernel" state of talking to each other about their differentiation and opportunities to collaborate. Think of this like the device-driver equivalent of the common memory-management infrastructure for confidential-computing being built up in KVM. As for establishing an "upstream path for cross-vendor confidential-computing device driver infrastructure" this is something I want to discuss at Plumbers. At present, the multiple vendor proposals for assigning devices to confidential computing VMs likely needs a new dedicated repository and maintainer team, but that is a discussion for v6.8. For now, Greg and Thomas have acked this approach and this is passing is AMD, Intel, and Google tests. Summary: - Introduce configfs-tsm as a shared ABI for confidential computing attestation reports - Convert sev-guest to additionally support configfs-tsm alongside its vendor specific ioctl() - Added signed attestation report retrieval to the tdx-guest driver forgoing a new vendor specific ioctl() - Misc cleanups and a new __free() annotation for kvfree()" * tag 'tsm-for-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/linux: virt: tdx-guest: Add Quote generation support using TSM_REPORTS virt: sevguest: Add TSM_REPORTS support for SNP_GET_EXT_REPORT mm/slab: Add __free() support for kvfree virt: sevguest: Prep for kernel internal get_ext_report() configfs-tsm: Introduce a shared ABI for attestation reports virt: coco: Add a coco/Makefile and coco/Kconfig virt: sevguest: Fix passing a stack buffer as a scatterlist target

Merge tag 'hardening-v6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2023-10-31T05:09:55Z

Pull hardening updates from Kees Cook: "One of the more voluminous set of changes is for adding the new __counted_by annotation[1] to gain run-time bounds checking of dynamically sized arrays with UBSan. - Add LKDTM test for stuck CPUs (Mark Rutland) - Improve LKDTM selftest behavior under UBSan (Ricardo Cañuelo) - Refactor more 1-element arrays into flexible arrays (Gustavo A. R. Silva) - Analyze and replace strlcpy and strncpy uses (Justin Stitt, Azeem Shaikh) - Convert group_info.usage to refcount_t (Elena Reshetova) - Add __counted_by annotations (Kees Cook, Gustavo A. R. Silva) - Add Kconfig fragment for basic hardening options (Kees Cook, Lukas Bulwahn) - Fix randstruct GCC plugin performance mode to stay in groups (Kees Cook) - Fix strtomem() compile-time check for small sources (Kees Cook)" * tag 'hardening-v6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (56 commits) hwmon: (acpi_power_meter) replace open-coded kmemdup_nul reset: Annotate struct reset_control_array with __counted_by kexec: Annotate struct crash_mem with __counted_by virtio_console: Annotate struct port_buffer with __counted_by ima: Add __counted_by for struct modsig and use struct_size() MAINTAINERS: Include stackleak paths in hardening entry string: Adjust strtomem() logic to allow for smaller sources hardening: x86: drop reference to removed config AMD_IOMMU_V2 randstruct: Fix gcc-plugin performance mode to stay in group mailbox: zynqmp: Annotate struct zynqmp_ipi_pdata with __counted_by drivers: thermal: tsens: Annotate struct tsens_priv with __counted_by irqchip/imx-intmux: Annotate struct intmux_data with __counted_by KVM: Annotate struct kvm_irq_routing_table with __counted_by virt: acrn: Annotate struct vm_memory_region_batch with __counted_by hwmon: Annotate struct gsc_hwmon_platform_data with __counted_by sparc: Annotate struct cpuinfo_tree with __counted_by isdn: kcapi: replace deprecated strncpy with strscpy_pad isdn: replace deprecated strncpy with strscpy NFS/flexfiles: Annotate struct nfs4_ff_layout_segment with __counted_by nfs41: Annotate struct nfs4_file_layout_dsaddr with __counted_by ...

virt: tdx-guest: Add Quote generation support using TSM_REPORTS

2023-10-20T01:12:00Z

In TDX guest, the attestation process is used to verify the TDX guest trustworthiness to other entities before provisioning secrets to the guest. The first step in the attestation process is TDREPORT generation, which involves getting the guest measurement data in the format of TDREPORT, which is further used to validate the authenticity of the TDX guest. TDREPORT by design is integrity-protected and can only be verified on the local machine. To support remote verification of the TDREPORT in a SGX-based attestation, the TDREPORT needs to be sent to the SGX Quoting Enclave (QE) to convert it to a remotely verifiable Quote. SGX QE by design can only run outside of the TDX guest (i.e. in a host process or in a normal VM) and guest can use communication channels like vsock or TCP/IP to send the TDREPORT to the QE. But for security concerns, the TDX guest may not support these communication channels. To handle such cases, TDX defines a GetQuote hypercall which can be used by the guest to request the host VMM to communicate with the SGX QE. More details about GetQuote hypercall can be found in TDX Guest-Host Communication Interface (GHCI) for Intel TDX 1.0, section titled "TDG.VP.VMCALL". Trusted Security Module (TSM) [1] exposes a common ABI for Confidential Computing Guest platforms to get the measurement data via ConfigFS. Extend the TSM framework and add support to allow an attestation agent to get the TDX Quote data (included usage example below). report=/sys/kernel/config/tsm/report/report0 mkdir $report dd if=/dev/urandom bs=64 count=1 > $report/inblob hexdump -C $report/outblob rmdir $report GetQuote TDVMCALL requires TD guest pass a 4K aligned shared buffer with TDREPORT data as input, which is further used by the VMM to copy the TD Quote result after successful Quote generation. To create the shared buffer, allocate a large enough memory and mark it shared using set_memory_decrypted() in tdx_guest_init(). This buffer will be re-used for GetQuote requests in the TDX TSM handler. Although this method reserves a fixed chunk of memory for GetQuote requests, such one time allocation can help avoid memory fragmentation related allocation failures later in the uptime of the guest. Since the Quote generation process is not time-critical or frequently used, the current version uses a polling model for Quote requests and it also does not support parallel GetQuote requests. Link: https://lore.kernel.org/lkml/169342399185.3934343.3035845348326944519.stgit@dwillia2-xfh.jf.intel.com/ [1] Signed-off-by: Kuppuswamy Sathyanarayanan Reviewed-by: Erdem Aktas Tested-by: Kuppuswamy Sathyanarayanan Tested-by: Peter Gonda Reviewed-by: Tom Lendacky Signed-off-by: Dan Williams

virt: sevguest: Add TSM_REPORTS support for SNP_GET_EXT_REPORT

2023-10-20T01:11:49Z

The sevguest driver was a first mover in the confidential computing space. As a first mover that afforded some leeway to build the driver without concern for common infrastructure. Now that sevguest is no longer a singleton [1] the common operation of building and transmitting attestation report blobs can / should be made common. In this model the so called "TSM-provider" implementations can share a common envelope ABI even if the contents of that envelope remain vendor-specific. When / if the industry agrees on an attestation record format, that definition can also fit in the same ABI. In the meantime the kernel's maintenance burden is reduced and collaboration on the commons is increased. Convert sevguest to use CONFIG_TSM_REPORTS to retrieve the data that the SNP_GET_EXT_REPORT ioctl produces. An example flow follows for retrieving the report blob via the TSM interface utility, assuming no nonce and VMPL==2: report=/sys/kernel/config/tsm/report/report0 mkdir $report echo 2 > $report/privlevel dd if=/dev/urandom bs=64 count=1 > $report/inblob hexdump -C $report/outblob # SNP report hexdump -C $report/auxblob # cert_table rmdir $report Given that the platform implementation is free to return empty certificate data if none is available it lets configfs-tsm be simplified as it only needs to worry about wrapping SNP_GET_EXT_REPORT, and leave SNP_GET_REPORT alone. The old ioctls can be lazily deprecated, the main motivation of this effort is to stop the proliferation of new ioctls, and to increase cross-vendor collaboration. Link: http://lore.kernel.org/r/64961c3baf8ce_142af829436@dwillia2-xfh.jf.intel.com.notmuch [1] Cc: Borislav Petkov Cc: Tom Lendacky Cc: Dionna Glaze Cc: Jeremi Piotrowski Tested-by: Kuppuswamy Sathyanarayanan Tested-by: Alexey Kardashevskiy Reviewed-by: Tom Lendacky Signed-off-by: Dan Williams

virt: sevguest: Prep for kernel internal get_ext_report()

2023-10-20T01:11:38Z

In preparation for using the configs-tsm facility to convey attestation blobs to userspace, switch to using the 'sockptr' api for copying payloads to provided buffers where 'sockptr' handles user vs kernel buffers. While configfs-tsm is meant to replace existing confidential computing ioctl() implementations for attestation report retrieval the old ioctl() path needs to stick around for a deprecation period. No behavior change intended. Cc: Borislav Petkov Cc: Tom Lendacky Cc: Dionna Glaze Reviewed-by: Kuppuswamy Sathyanarayanan Tested-by: Kuppuswamy Sathyanarayanan Reviewed-by: Tom Lendacky Signed-off-by: Dan Williams

configfs-tsm: Introduce a shared ABI for attestation reports

2023-10-20T01:11:38Z

One of the common operations of a TSM (Trusted Security Module) is to provide a way for a TVM (confidential computing guest execution environment) to take a measurement of its launch state, sign it and submit it to a verifying party. Upon successful attestation that verifies the integrity of the TVM additional secrets may be deployed. The concept is common across TSMs, but the implementations are unfortunately vendor specific. While the industry grapples with a common definition of this attestation format [1], Linux need not make this problem worse by defining a new ABI per TSM that wants to perform a similar operation. The current momentum has been to invent new ioctl-ABI per TSM per function which at best is an abdication of the kernel's responsibility to make common infrastructure concepts share common ABI. The proposal, targeted to conceptually work with TDX, SEV-SNP, COVE if not more, is to define a configfs interface to retrieve the TSM-specific blob. report=/sys/kernel/config/tsm/report/report0 mkdir $report dd if=binary_userdata_plus_nonce > $report/inblob hexdump $report/outblob This approach later allows for the standardization of the attestation blob format without needing to invent a new ABI. Once standardization happens the standard format can be emitted by $report/outblob and indicated by $report/provider, or a new attribute like "$report/tcg_coco_report" can emit the standard format alongside the vendor format. Review of previous iterations of this interface identified that there is a need to scale report generation for multiple container environments [2]. Configfs enables a model where each container can bind mount one or more report generation item instances. Still, within a container only a single thread can be manipulating a given configuration instance at a time. A 'generation' count is provided to detect conflicts between multiple threads racing to configure a report instance. The SEV-SNP concepts of "extended reports" and "privilege levels" are optionally enabled by selecting 'tsm_report_ext_type' at register_tsm() time. The expectation is that those concepts are generic enough that they may be adopted by other TSM implementations. In other words, configfs-tsm aims to address a superset of TSM specific functionality with a common ABI where attributes may appear, or not appear, based on the set of concepts the implementation supports. Link: http://lore.kernel.org/r/64961c3baf8ce_142af829436@dwillia2-xfh.jf.intel.com.notmuch [1] Link: http://lore.kernel.org/r/57f3a05e-8fcd-4656-beea-56bb8365ae64@linux.microsoft.com [2] Cc: Kuppuswamy Sathyanarayanan Cc: Dionna Amalie Glaze Cc: James Bottomley Cc: Peter Gonda Cc: Greg Kroah-Hartman Cc: Samuel Ortiz Acked-by: Greg Kroah-Hartman Acked-by: Thomas Gleixner Reviewed-by: Kuppuswamy Sathyanarayanan Tested-by: Kuppuswamy Sathyanarayanan Reviewed-by: Tom Lendacky Signed-off-by: Dan Williams

virt: coco: Add a coco/Makefile and coco/Kconfig

2023-10-20T01:11:38Z

In preparation for adding another coco build target, relieve drivers/virt/Makefile of the responsibility to track new compilation unit additions to drivers/virt/coco/, and do the same for drivers/virt/Kconfig. Reviewed-by: Kuppuswamy Sathyanarayanan Tested-by: Kuppuswamy Sathyanarayanan Reviewed-by: Tom Lendacky Signed-off-by: Dan Williams

virt: sevguest: Fix passing a stack buffer as a scatterlist target

2023-10-11T03:03:53Z

CONFIG_DEBUG_SG highlights that get_{report,ext_report,derived_key)()} are passing stack buffers as the @req_buf argument to handle_guest_request(), generating a Call Trace of the following form: WARNING: CPU: 0 PID: 1175 at include/linux/scatterlist.h:187 enc_dec_message+0x518/0x5b0 [sev_guest] [..] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 RIP: 0010:enc_dec_message+0x518/0x5b0 [sev_guest] Call Trace: [..] handle_guest_request+0x135/0x520 [sev_guest] get_ext_report+0x1ec/0x3e0 [sev_guest] snp_guest_ioctl+0x157/0x200 [sev_guest] Note that the above Call Trace was with the DEBUG_SG BUG_ON()s converted to WARN_ON()s. This is benign as long as there are no hardware crypto accelerators loaded for the aead cipher, and no subsequent dma_map_sg() is performed on the scatterlist. However, sev-guest can not assume the presence of an aead accelerator nor can it assume that CONFIG_DEBUG_SG is disabled. Resolve this bug by allocating virt_addr_valid() memory, similar to the other buffers am @snp_dev instance carries, to marshal requests from user buffers to kernel buffers. Reported-by: Peter Gonda Closes: http://lore.kernel.org/r/CAMkAt6r2VPPMZ__SQfJse8qWsUyYW3AgYbOUVM0S_Vtk=KvkxQ@mail.gmail.com Fixes: fce96cf04430 ("virt: Add SEV-SNP guest driver") Cc: Borislav Petkov Cc: Tom Lendacky Cc: Dionna Glaze Cc: Jeremi Piotrowski Tested-by: Kuppuswamy Sathyanarayanan Reviewed-by: Tom Lendacky Signed-off-by: Dan Williams

x86/cpu: Encapsulate topology information in cpuinfo_x86

2023-10-10T12:38:17Z

The topology related information is randomly scattered across cpuinfo_x86. Create a new structure cpuinfo_topo and move in a first step initial_apicid and apicid into it. Aside of being better readable this is in preparation for replacing the horribly fragile CPU topology evaluation code further down the road. Consolidate APIC ID fields to u32 as that represents the hardware type. No functional change. Signed-off-by: Thomas Gleixner Tested-by: Juergen Gross Tested-by: Sohil Mehta Tested-by: Michael Kelley Tested-by: Peter Zijlstra (Intel) Tested-by: Zhang Rui Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20230814085112.269787744@linutronix.de

virt: acrn: Annotate struct vm_memory_region_batch with __counted_by

2023-10-09T05:46:04Z

Prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions). As found with Coccinelle[1], add __counted_by for struct vm_memory_region_batch. Additionally, since the element count member must be set before accessing the annotated flexible array member, move its initialization earlier. [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci Cc: Fei Li Reviewed-by: "Gustavo A. R. Silva" Link: https://lore.kernel.org/r/20230922175102.work.020-kees@kernel.org Signed-off-by: Kees Cook