On 5/15/2024 6:39 AM, Michael Kelley wrote:
From: Roman Kisel <romank@xxxxxxxxxxxxxxxxxxx> Sent: Tuesday, May 14, 2024 3:44 PMTo run in the VTL mode, Hyper-V drivers have to know what VTL the system boots in, and the arm64/hyperv code does not update the variable that stores the value. Update the variable to enable the Hyper-V drivers to boot in the VTL mode and print the VTL the code runs in. Signed-off-by: Roman Kisel <romank@xxxxxxxxxxxxxxxxxxx> --- arch/arm64/hyperv/Makefile | 1 + arch/arm64/hyperv/hv_vtl.c | 19 +++++++++++++++++++ arch/arm64/hyperv/mshyperv.c | 6 ++++++ arch/arm64/include/asm/mshyperv.h | 8 ++++++++ arch/x86/hyperv/hv_vtl.c | 2 +- 5 files changed, 35 insertions(+), 1 deletion(-) create mode 100644 arch/arm64/hyperv/hv_vtl.c diff --git a/arch/arm64/hyperv/Makefile b/arch/arm64/hyperv/Makefile index 87c31c001da9..9701a837a6e1 100644 --- a/arch/arm64/hyperv/Makefile +++ b/arch/arm64/hyperv/Makefile @@ -1,2 +1,3 @@ # SPDX-License-Identifier: GPL-2.0 obj-y := hv_core.o mshyperv.o +obj-$(CONFIG_HYPERV_VTL_MODE) += hv_vtl.o diff --git a/arch/arm64/hyperv/hv_vtl.c b/arch/arm64/hyperv/hv_vtl.c new file mode 100644 index 000000000000..9b44cc49594c --- /dev/null +++ b/arch/arm64/hyperv/hv_vtl.c @@ -0,0 +1,19 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2023, Microsoft, Inc. + * + * Author : Roman Kisel <romank@xxxxxxxxxxxxxxxxxxx> + */ + +#include <asm/mshyperv.h> + +void __init hv_vtl_init_platform(void) +{ + pr_info("Linux runs in Hyper-V Virtual Trust Level %d\n", ms_hyperv.vtl); +} + +int __init hv_vtl_early_init(void) +{ + return 0; +} +early_initcall(hv_vtl_early_init); diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c index 208a3bcb9686..cbde483b167a 100644 --- a/arch/arm64/hyperv/mshyperv.c +++ b/arch/arm64/hyperv/mshyperv.c @@ -96,6 +96,12 @@ static int __init hyperv_init(void) return ret; } + /* Find the VTL */ + ms_hyperv.vtl = get_vtl(); + if (ms_hyperv.vtl > 0) /* non default VTL */ + hv_vtl_early_init();Since hv_vtl_early_init() doesn't do anything on arm64, is the above and the empty implementation of hv_vtl_early_init() really needed? I thought maybe a subsequent patch in this series would populate hv_vtl_early_init() to do something, but I didn't see such. I realize the functions hv_vtl_init_platform() and hv_vtl_early_init() parallel equivalent functions on x86, but I'd say drop hv_vtl_early_init() on arm64 if it isn't needed. Note too that the naming on the x86 side is arguably a bit messed up. hv_vtl_init_platform() runs *before* hv_vtl_early_init(). But typically in the Linux kernel, functions with "early init" in the name run very early in boot, and that's not the case here. hv_vtl_init_platform() is actually the function that runs very early in boot, but its name is set up to parallel ms_hyperv_init_platform(), which calls it. On the x86 side, I'd would argue for renaming hv_vtl_init_platform() to hv_vtl_early_init(), and then hv_vtl_early_init() becomes hv_vtl_init(). But that's probably a separate patch. Here on arm64, perhaps all you need is hv_vtl_init().
I'll clean that up, appreciate the thorough explanation!
Michael+ + hv_vtl_init_platform(); ms_hyperv_late_init(); hyperv_initialized = true; diff --git a/arch/arm64/include/asm/mshyperv.h b/arch/arm64/include/asm/mshyperv.h index a975e1a689dd..4a8ff6be389c 100644 --- a/arch/arm64/include/asm/mshyperv.h +++ b/arch/arm64/include/asm/mshyperv.h @@ -49,6 +49,14 @@ static inline u64 hv_get_msr(unsigned int reg) ARM_SMCCC_OWNER_VENDOR_HYP, \ HV_SMCCC_FUNC_NUMBER) +#ifdef CONFIG_HYPERV_VTL_MODE +void __init hv_vtl_init_platform(void); +int __init hv_vtl_early_init(void); +#else +static inline void __init hv_vtl_init_platform(void) {} +static inline int __init hv_vtl_early_init(void) { return 0; } +#endif + #include <asm-generic/mshyperv.h> #endif diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c index 92bd5a55f093..ae3105375a12 100644 --- a/arch/x86/hyperv/hv_vtl.c +++ b/arch/x86/hyperv/hv_vtl.c @@ -19,7 +19,7 @@ static struct real_mode_header hv_vtl_real_mode_header; void __init hv_vtl_init_platform(void) { - pr_info("Linux runs in Hyper-V Virtual Trust Level\n"); + pr_info("Linux runs in Hyper-V Virtual Trust Level %d\n", ms_hyperv.vtl); x86_platform.realmode_reserve = x86_init_noop; x86_platform.realmode_init = x86_init_noop; -- 2.45.0
-- Thank you, Roman
