linux/include/asm-generic/mshyperv.h, branch v6.4

x86/hyperv: Add callback filter to cpumask_to_vpset()

2023-04-17T19:19:05Z

When copying CPUs from a Linux cpumask to a Hyper-V VPset, cpumask_to_vpset() currently has a "_noself" variant that doesn't copy the current CPU to the VPset. Generalize this variant by replacing it with a "_skip" variant having a callback function that is invoked for each CPU to decide if that CPU should be copied. Update the one caller of cpumask_to_vpset_noself() to use the new "_skip" variant instead. No functional change. Signed-off-by: Michael Kelley Link: https://lore.kernel.org/r/1679922967-26582-2-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu

hv_netvsc: Remove second mapping of send and recv buffers

2023-04-17T19:19:04Z

With changes to how Hyper-V guest VMs flip memory between private (encrypted) and shared (decrypted), creating a second kernel virtual mapping for shared memory is no longer necessary. Everything needed for the transition to shared is handled by set_memory_decrypted(). As such, remove the code to create and manage the second mapping for the pre-allocated send and recv buffers. This mapping is the last user of hv_map_memory()/hv_unmap_memory(), so delete these functions as well. Finally, hv_map_memory() is the last user of vmap_pfn() in Hyper-V guest code, so remove the Kconfig selection of VMAP_PFN. Signed-off-by: Michael Kelley Reviewed-by: Tianyu Lan Link: https://lore.kernel.org/r/1679838727-87310-11-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu

x86/hyperv: Change vTOM handling to use standard coco mechanisms

2023-03-27T07:31:43Z

Hyper-V guests on AMD SEV-SNP hardware have the option of using the "virtual Top Of Memory" (vTOM) feature specified by the SEV-SNP architecture. With vTOM, shared vs. private memory accesses are controlled by splitting the guest physical address space into two halves. vTOM is the dividing line where the uppermost bit of the physical address space is set; e.g., with 47 bits of guest physical address space, vTOM is 0x400000000000 (bit 46 is set). Guest physical memory is accessible at two parallel physical addresses -- one below vTOM and one above vTOM. Accesses below vTOM are private (encrypted) while accesses above vTOM are shared (decrypted). In this sense, vTOM is like the GPA.SHARED bit in Intel TDX. Support for Hyper-V guests using vTOM was added to the Linux kernel in two patch sets[1][2]. This support treats the vTOM bit as part of the physical address. For accessing shared (decrypted) memory, these patch sets create a second kernel virtual mapping that maps to physical addresses above vTOM. A better approach is to treat the vTOM bit as a protection flag, not as part of the physical address. This new approach is like the approach for the GPA.SHARED bit in Intel TDX. Rather than creating a second kernel virtual mapping, the existing mapping is updated using recently added coco mechanisms. When memory is changed between private and shared using set_memory_decrypted() and set_memory_encrypted(), the PTEs for the existing kernel mapping are changed to add or remove the vTOM bit in the guest physical address, just as with TDX. The hypercalls to change the memory status on the host side are made using the existing callback mechanism. Everything just works, with a minor tweak to map the IO-APIC to use private accesses. To accomplish the switch in approach, the following must be done: * Update Hyper-V initialization to set the cc_mask based on vTOM and do other coco initialization. * Update physical_mask so the vTOM bit is no longer treated as part of the physical address * Remove CC_VENDOR_HYPERV and merge the associated vTOM functionality under CC_VENDOR_AMD. Update cc_mkenc() and cc_mkdec() to set/clear the vTOM bit as a protection flag. * Code already exists to make hypercalls to inform Hyper-V about pages changing between shared and private. Update this code to run as a callback from __set_memory_enc_pgtable(). * Remove the Hyper-V special case from __set_memory_enc_dec() * Remove the Hyper-V specific call to swiotlb_update_mem_attributes() since mem_encrypt_init() will now do it. * Add a Hyper-V specific implementation of the is_private_mmio() callback that returns true for the IO-APIC and vTPM MMIO addresses [1] https://lore.kernel.org/all/20211025122116.264793-1-ltykernel@gmail.com/ [2] https://lore.kernel.org/all/20211213071407.314309-1-ltykernel@gmail.com/ [ bp: Touchups. ] Signed-off-by: Michael Kelley Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/1679838727-87310-7-git-send-email-mikelley@microsoft.com

x86/hyperv: Add support for detecting nested hypervisor

2023-01-12T15:23:26Z

Detect if Linux is running as a nested hypervisor in the root partition for Microsoft Hypervisor, using flags provided by MSHV. Expose a new variable hv_nested that is used later for decisions specific to the nested use case. Signed-off-by: Jinank Jain Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/8e3e7112806e81d2292a66a56fe547162754ecea.1672639707.git.jinankjain@linux.microsoft.com Signed-off-by: Wei Liu

x86/hyperv: Introduce HV_MAX_SPARSE_VCPU_BANKS/HV_VCPUS_PER_SPARSE_BANK constants

2022-11-18T17:59:07Z

It may not come clear from where the magical '64' value used in __cpumask_to_vpset() come from. Moreover, '64' means both the maximum sparse bank number as well as the number of vCPUs per bank. Add defines to make things clear. These defines are also going to be used by KVM. No functional change. Reviewed-by: Maxim Levitsky Reviewed-by: Sean Christopherson Signed-off-by: Vitaly Kuznetsov Signed-off-by: Paolo Bonzini Message-Id: <20221101145426.251680-15-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini

hyperv: simplify and rename generate_guest_id

2022-09-28T13:36:56Z

The generate_guest_id function is more suitable for use after the following modifications. 1. The return value of the function is modified to u64. 2. Remove the d_info1 and d_info2 parameters from the function, keep the u64 type kernel_version parameter. 3. Rename the function to make it clearly a Hyper-V related function, and modify it to hv_generate_guest_id. Signed-off-by: Li kunyu Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20220928064046.3545-1-kunyu@nfschina.com Signed-off-by: Wei Liu

Drivers: hv: vmbus: Propagate VMbus coherence to each VMbus device

2022-03-29T12:12:50Z

VMbus synthetic devices are not represented in the ACPI DSDT -- only the top level VMbus device is represented. As a result, on ARM64 coherence information in the _CCA method is not specified for synthetic devices, so they default to not hardware coherent. Drivers for some of these synthetic devices have been recently updated to use the standard DMA APIs, and they are incurring extra overhead of unneeded software coherence management. Fix this by propagating coherence information from the VMbus node in ACPI to the individual synthetic devices. There's no effect on x86/x64 where devices are always hardware coherent. Signed-off-by: Michael Kelley Acked-by: Robin Murphy Link: https://lore.kernel.org/r/1648138492-2191-2-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu

Drivers: hv: Fix definition of hypercall input & output arg variables

2021-12-28T14:18:43Z

The percpu variables hyperv_pcpu_input_arg and hyperv_pcpu_output_arg have been incorrectly defined since their inception. The __percpu qualifier should be associated with the void * (i.e., a pointer), not with the target of the pointer. This distinction makes no difference to gcc and the generated code, but sparse correctly complains. Fix the definitions in the interest of general correctness in addition to making sparse happy. No functional change. Reported-by: kernel test robot Signed-off-by: Michael Kelley Link: https://lore.kernel.org/r/1640662315-22260-1-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu

net: netvsc: Add Isolation VM support for netvsc driver

2021-12-20T18:01:09Z

In Isolation VM, all shared memory with host needs to mark visible to host via hvcall. vmbus_establish_gpadl() has already done it for netvsc rx/tx ring buffer. The page buffer used by vmbus_sendpacket_ pagebuffer() stills need to be handled. Use DMA API to map/umap these memory during sending/receiving packet and Hyper-V swiotlb bounce buffer dma address will be returned. The swiotlb bounce buffer has been masked to be visible to host during boot up. rx/tx ring buffer is allocated via vzalloc() and they need to be mapped into unencrypted address space(above vTOM) before sharing with host and accessing. Add hv_map/unmap_memory() to map/umap rx /tx ring buffer. Signed-off-by: Tianyu Lan Reviewed-by: Haiyang Zhang Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20211213071407.314309-6-ltykernel@gmail.com Signed-off-by: Wei Liu

x86/hyperv: Add ghcb hvcall support for SNP VM

2021-10-28T11:22:49Z

hyperv provides ghcb hvcall to handle VMBus HVCALL_SIGNAL_EVENT and HVCALL_POST_MESSAGE msg in SNP Isolation VM. Add such support. Reviewed-by: Michael Kelley Signed-off-by: Tianyu Lan Link: https://lore.kernel.org/r/20211025122116.264793-8-ltykernel@gmail.com Signed-off-by: Wei Liu