kernel.git/arch/x86/include/asm/mshyperv.h, branch linux-6.15.y

x86/hyperv: Fix APIC ID and VP index confusion in hv_snp_boot_ap()

2025-06-19T13:41:07Z

commit 86c48271e0d60c82665e9fd61277002391efcef7 upstream. To start an application processor in SNP-isolated guest, a hypercall is used that takes a virtual processor index. The hv_snp_boot_ap() function uses that START_VP hypercall but passes as VP index to it what it receives as a wakeup_secondary_cpu_64 callback: the APIC ID. As those two aren't generally interchangeable, that may lead to hung APs if the VP index and the APIC ID don't match up. Update the parameter names to avoid confusion as to what the parameter is. Use the APIC ID to the VP index conversion to provide the correct input to the hypercall. Cc: stable@vger.kernel.org Fixes: 44676bb9d566 ("x86/hyperv: Add smp support for SEV-SNP guest") Signed-off-by: Roman Kisel Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20250507182227.7421-2-romank@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <20250507182227.7421-2-romank@linux.microsoft.com> Signed-off-by: Greg Kroah-Hartman

Merge tag 'hyperv-next-signed-20250324' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

2025-03-25T21:47:04Z

Pull hyperv updates from Wei Liu: - Add support for running as the root partition in Hyper-V (Microsoft Hypervisor) by exposing /dev/mshv (Nuno and various people) - Add support for CPU offlining in Hyper-V (Hamza Mahfooz) - Misc fixes and cleanups (Roman Kisel, Tianyu Lan, Wei Liu, Michael Kelley, Thorsten Blum) * tag 'hyperv-next-signed-20250324' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (24 commits) x86/hyperv: fix an indentation issue in mshyperv.h x86/hyperv: Add comments about hv_vpset and var size hypercall input args Drivers: hv: Introduce mshv_root module to expose /dev/mshv to VMMs hyperv: Add definitions for root partition driver to hv headers x86: hyperv: Add mshv_handler() irq handler and setup function Drivers: hv: Introduce per-cpu event ring tail Drivers: hv: Export some functions for use by root partition module acpi: numa: Export node_to_pxm() hyperv: Introduce hv_recommend_using_aeoi() arm64/hyperv: Add some missing functions to arm64 x86/mshyperv: Add support for extended Hyper-V features hyperv: Log hypercall status codes as strings x86/hyperv: Fix check of return value from snp_set_vmsa() x86/hyperv: Add VTL mode callback for restarting the system x86/hyperv: Add VTL mode emergency restart callback hyperv: Remove unused union and structs hyperv: Add CONFIG_MSHV_ROOT to gate root partition support hyperv: Change hv_root_partition into a function hyperv: Convert hypercall statuses to linux error codes drivers/hv: add CPU offlining support ...

x86/hyperv: fix an indentation issue in mshyperv.h

2025-03-21T22:41:56Z

Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202503220640.hjiacW2C-lkp@intel.com/ Signed-off-by: Wei Liu

x86/hyperv: Use named operands in inline asm

2025-03-04T10:21:39Z

Use named operands in inline asm to make it easier to change the constraint order. Do this in preparation of changing the ASM_CALL_CONSTRAINT primitive. Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Acked-by: Peter Zijlstra (Intel) Cc: "K. Y. Srinivasan" Cc: Haiyang Zhang Cc: Wei Liu Cc: Dexuan Cui Cc: linux-kernel@vger.kernel.org

hyperv: Move arch/x86/hyperv/hv_proc.c to drivers/hv

2025-02-13T23:38:47Z

These helpers are not specific to x86_64 and will be needed by common code. Remove some unnecessary #includes. Reviewed-by: Michael Kelley Signed-off-by: Nuno Das Neves Link: https://lore.kernel.org/r/1738955002-20821-3-git-send-email-nunodasneves@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <1738955002-20821-3-git-send-email-nunodasneves@linux.microsoft.com>

hyperv: Move hv_current_partition_id to arch-generic code

2025-02-13T23:38:47Z

Move hv_current_partition_id and hv_get_partition_id() to hv_common.c, and call hv_get_partition_id() on arm64 in hyperv_init(). These aren't specific to x86_64 and will be needed by common code. Set hv_current_partition_id to HV_PARTITION_ID_SELF by default. Rename struct hv_get_partition_id to hv_output_get_partition_id, to make it distinct from the function hv_get_partition_id(), and match the original Hyper-V struct name. Remove the BUG()s. Failing to get the id need not crash the machine. Signed-off-by: Nuno Das Neves Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/1738955002-20821-2-git-send-email-nunodasneves@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <1738955002-20821-2-git-send-email-nunodasneves@linux.microsoft.com>

hyperv: Switch from hyperv-tlfs.h to hyperv/hvhdk.h

2025-01-10T00:54:21Z

Switch to using hvhdk.h everywhere in the kernel. This header includes all the new Hyper-V headers in include/hyperv, which form a superset of the definitions found in hyperv-tlfs.h. This makes it easier to add new Hyper-V interfaces without being restricted to those in the TLFS doc (reflected in hyperv-tlfs.h). To be more consistent with the original Hyper-V code, the names of some definitions are changed slightly. Update those where needed. Update comments in mshyperv.h files to point to include/hyperv for adding new definitions. Signed-off-by: Nuno Das Neves Reviewed-by: Michael Kelley Reviewed-by: Easwar Hariharan Signed-off-by: Roman Kisel Reviewed-by: Easwar Hariharan Link: https://lore.kernel.org/r/1732577084-2122-5-git-send-email-nunodasneves@linux.microsoft.com Link: https://lore.kernel.org/r/20250108222138.1623703-3-romank@linux.microsoft.com Signed-off-by: Wei Liu

hyperv: Clean up unnecessary #includes

2025-01-08T08:18:27Z

Remove includes of linux/hyperv.h, mshyperv.h, and hyperv-tlfs.h where they are not used. Signed-off-by: Nuno Das Neves Acked-by: Wei Liu Reviewed-by: Michael Kelley Reviewed-by: Easwar Hariharan Link: https://lore.kernel.org/r/1732577084-2122-3-git-send-email-nunodasneves@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <1732577084-2122-3-git-send-email-nunodasneves@linux.microsoft.com>

x86/hyperv: fix kexec crash due to VP assist page corruption

2024-09-05T07:21:37Z

commit 9636be85cc5b ("x86/hyperv: Fix hyperv_pcpu_input_arg handling when CPUs go online/offline") introduces a new cpuhp state for hyperv initialization. cpuhp_setup_state() returns the state number if state is CPUHP_AP_ONLINE_DYN or CPUHP_BP_PREPARE_DYN and 0 for all other states. For the hyperv case, since a new cpuhp state was introduced it would return 0. However, in hv_machine_shutdown(), the cpuhp_remove_state() call is conditioned upon "hyperv_init_cpuhp > 0". This will never be true and so hv_cpu_die() won't be called on all CPUs. This means the VP assist page won't be reset. When the kexec kernel tries to setup the VP assist page again, the hypervisor corrupts the memory region of the old VP assist page causing a panic in case the kexec kernel is using that memory elsewhere. This was originally fixed in commit dfe94d4086e4 ("x86/hyperv: Fix kexec panic/hang issues"). Get rid of hyperv_init_cpuhp entirely since we are no longer using a dynamic cpuhp state and use CPUHP_AP_HYPERV_ONLINE directly with cpuhp_remove_state(). Cc: stable@vger.kernel.org Fixes: 9636be85cc5b ("x86/hyperv: Fix hyperv_pcpu_input_arg handling when CPUs go online/offline") Signed-off-by: Anirudh Rayabharam (Microsoft) Reviewed-by: Vitaly Kuznetsov Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20240828112158.3538342-1-anirudh@anirudhrb.com Signed-off-by: Wei Liu Message-ID: <20240828112158.3538342-1-anirudh@anirudhrb.com>

hyperv-tlfs: Change prefix of generic HV_REGISTER_* MSRs to HV_MSR_*

2024-03-04T06:59:18Z

The HV_REGISTER_ are used as arguments to hv_set/get_register(), which delegate to arch-specific mechanisms for getting/setting synthetic Hyper-V MSRs. On arm64, HV_REGISTER_ defines are synthetic VP registers accessed via the get/set vp registers hypercalls. The naming matches the TLFS document, although these register names are not specific to arm64. However, on x86 the prefix HV_REGISTER_ indicates Hyper-V MSRs accessed via rdmsrl()/wrmsrl(). This is not consistent with the TLFS doc, where HV_REGISTER_ is *only* used for used for VP register names used by the get/set register hypercalls. To fix this inconsistency and prevent future confusion, change the arch-generic aliases used by callers of hv_set/get_register() to have the prefix HV_MSR_ instead of HV_REGISTER_. Use the prefix HV_X64_MSR_ for the x86-only Hyper-V MSRs. On x86, the generic HV_MSR_'s point to the corresponding HV_X64_MSR_. Move the arm64 HV_REGISTER_* defines to the asm-generic hyperv-tlfs.h, since these are not specific to arm64. On arm64, the generic HV_MSR_'s point to the corresponding HV_REGISTER_. While at it, rename hv_get/set_registers() and related functions to hv_get/set_msr(), hv_get/set_nested_msr(), etc. These are only used for Hyper-V MSRs and this naming makes that clear. Signed-off-by: Nuno Das Neves Reviewed-by: Wei Liu Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/1708440933-27125-1-git-send-email-nunodasneves@linux.microsoft.com Signed-off-by: Wei Liu Message-ID: <1708440933-27125-1-git-send-email-nunodasneves@linux.microsoft.com>