From patchwork Fri Jul 26 22:59:06 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roman Kisel X-Patchwork-Id: 814595 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 6DFB614EC4E; Fri, 26 Jul 2024 22:59:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722034771; cv=none; b=LhZIVY464dxtTwbN/W1DDIXv5W4stjG9q7zPrjhB9lDI0TrI5VpAyXh5W0+uUKq8iiYq/G9OFsXpGq6sGuGIIyXv9oiHnKeT1r57tUYPhkDE/aJJifAjIaglL7iW7SUnYHAK8bkWb/4n9cKnfLaG6vn/2qFSix1766uhWNgPBoQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722034771; c=relaxed/simple; bh=Lssq5DYvn0UB3De1jCUCZOPpcxO9JEDZzy/E/cIrDls=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=OSbAItAnTTUdIX8qP3W9SRUXhscvp0TUpWqqIE+kPlLzRscniJsvR+YgmkCnY3BBDlKXQ4tqcTXBDdPaezensJzpEIJNfW99fOmAAxyfzwVSBnX2pLkVmYnG9nQ0JyUck/UQtVQlYY7eG8Fjr/bjWQr9C5cjfQW7JwOplXbMorg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=Ay3ecAMl; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="Ay3ecAMl" Received: from romank-3650.corp.microsoft.com (unknown [131.107.159.62]) by linux.microsoft.com (Postfix) with ESMTPSA id CEE3D20B7127; Fri, 26 Jul 2024 15:59:28 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com CEE3D20B7127 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1722034769; bh=aGtuuS44L1FWxWnw8aopWoYtUuyOCwVC3o0rFEImRa4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ay3ecAMlZzDzgdbwBOPeo/Jmf+KSFKuylv/Gf8gJBwUBwig9q2NhLAemzcG8ltPRV riKWHkp6130fkaOD9K/juYHtqmScjVjRoViUv5axRYPSEg0VFSVX6skSaUTMvxBk2Q Ct6fnu6En2IfZdKnhQbhNCdtbi3flTO7AuplpWoQ= From: Roman Kisel To: arnd@arndb.de, bhelgaas@google.com, bp@alien8.de, catalin.marinas@arm.com, dave.hansen@linux.intel.com, decui@microsoft.com, haiyangz@microsoft.com, hpa@zytor.com, kw@linux.com, kys@microsoft.com, lenb@kernel.org, lpieralisi@kernel.org, mingo@redhat.com, rafael@kernel.org, robh@kernel.org, tglx@linutronix.de, wei.liu@kernel.org, will@kernel.org, linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, x86@kernel.org Cc: apais@microsoft.com, benhill@microsoft.com, ssengar@microsoft.com, sunilmut@microsoft.com, vdso@hexbites.dev Subject: [PATCH v3 3/7] Drivers: hv: Provide arch-neutral implementation of get_vtl() Date: Fri, 26 Jul 2024 15:59:06 -0700 Message-Id: <20240726225910.1912537-4-romank@linux.microsoft.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240726225910.1912537-1-romank@linux.microsoft.com> References: <20240726225910.1912537-1-romank@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 To run in the VTL mode, Hyper-V drivers have to know what VTL the system boots in, and the arm64/hyperv code does not have the means to compute that. Refactor the code to hoist the function that detects VTL, make it arch-neutral to be able to employ it to get the VTL on arm64. Fix the hypercall output address in `get_vtl(void)` not to overlap with the hypercall input area to adhere to the Hyper-V TLFS. Signed-off-by: Roman Kisel --- arch/x86/hyperv/hv_init.c | 34 --------------------- arch/x86/include/asm/hyperv-tlfs.h | 7 ----- drivers/hv/hv_common.c | 47 ++++++++++++++++++++++++++++-- include/asm-generic/hyperv-tlfs.h | 7 +++++ include/asm-generic/mshyperv.h | 6 ++++ 5 files changed, 58 insertions(+), 43 deletions(-) diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 17a71e92a343..c350fa05ee59 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -413,40 +413,6 @@ static void __init hv_get_partition_id(void) local_irq_restore(flags); } -#if IS_ENABLED(CONFIG_HYPERV_VTL_MODE) -static u8 __init get_vtl(void) -{ - u64 control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_REGISTERS; - struct hv_get_vp_registers_input *input; - struct hv_get_vp_registers_output *output; - unsigned long flags; - u64 ret; - - local_irq_save(flags); - input = *this_cpu_ptr(hyperv_pcpu_input_arg); - output = (struct hv_get_vp_registers_output *)input; - - memset(input, 0, struct_size(input, element, 1)); - input->header.partitionid = HV_PARTITION_ID_SELF; - input->header.vpindex = HV_VP_INDEX_SELF; - input->header.inputvtl = 0; - input->element[0].name0 = HV_X64_REGISTER_VSM_VP_STATUS; - - ret = hv_do_hypercall(control, input, output); - if (hv_result_success(ret)) { - ret = output->as64.low & HV_X64_VTL_MASK; - } else { - pr_err("Failed to get VTL(error: %lld) exiting...\n", ret); - BUG(); - } - - local_irq_restore(flags); - return ret; -} -#else -static inline u8 get_vtl(void) { return 0; } -#endif - /* * This function is to be invoked early in the boot sequence after the * hypervisor has been detected. diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h index 3787d26810c1..9ee68eb8e6ff 100644 --- a/arch/x86/include/asm/hyperv-tlfs.h +++ b/arch/x86/include/asm/hyperv-tlfs.h @@ -309,13 +309,6 @@ enum hv_isolation_type { #define HV_MSR_STIMER0_CONFIG (HV_X64_MSR_STIMER0_CONFIG) #define HV_MSR_STIMER0_COUNT (HV_X64_MSR_STIMER0_COUNT) -/* - * Registers are only accessible via HVCALL_GET_VP_REGISTERS hvcall and - * there is not associated MSR address. - */ -#define HV_X64_REGISTER_VSM_VP_STATUS 0x000D0003 -#define HV_X64_VTL_MASK GENMASK(3, 0) - /* Hyper-V memory host visibility */ enum hv_mem_host_visibility { VMBUS_PAGE_NOT_VISIBLE = 0, diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c index 9c452bfbd571..7d6c1523b0b5 100644 --- a/drivers/hv/hv_common.c +++ b/drivers/hv/hv_common.c @@ -339,8 +339,8 @@ int __init hv_common_init(void) hyperv_pcpu_input_arg = alloc_percpu(void *); BUG_ON(!hyperv_pcpu_input_arg); - /* Allocate the per-CPU state for output arg for root */ - if (hv_root_partition) { + /* Allocate the per-CPU state for output arg for root or a VTL */ + if (hv_root_partition || IS_ENABLED(CONFIG_HYPERV_VTL_MODE)) { hyperv_pcpu_output_arg = alloc_percpu(void *); BUG_ON(!hyperv_pcpu_output_arg); } @@ -656,3 +656,46 @@ u64 __weak hv_tdx_hypercall(u64 control, u64 param1, u64 param2) return HV_STATUS_INVALID_PARAMETER; } EXPORT_SYMBOL_GPL(hv_tdx_hypercall); + +#if IS_ENABLED(CONFIG_HYPERV_VTL_MODE) +u8 __init get_vtl(void) +{ + u64 control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_REGISTERS; + struct hv_get_vp_registers_input *input; + struct hv_get_vp_registers_output *output; + unsigned long flags; + u64 ret; + + local_irq_save(flags); + input = *this_cpu_ptr(hyperv_pcpu_input_arg); + output = *this_cpu_ptr(hyperv_pcpu_output_arg); + + memset(input, 0, struct_size(input, element, 1)); + input->header.partitionid = HV_PARTITION_ID_SELF; + input->header.vpindex = HV_VP_INDEX_SELF; + input->header.inputvtl = 0; + input->element[0].name0 = HV_REGISTER_VSM_VP_STATUS; + + ret = hv_do_hypercall(control, input, output); + if (hv_result_success(ret)) { + ret = output->as64.low & HV_VTL_MASK; + } else { + pr_err("Failed to get VTL(error: %lld) exiting...\n", ret); + + /* + * This is a dead end, something fundamental is broken. + * + * There is no sensible way of continuing as the Hyper-V drivers + * transitively depend via the vmbus driver on knowing which VTL + * they run in to establish communication with the host. The kernel + * is going to be worse off if continued booting than a panicked one, + * just hung and stuck, producing second-order failures, with neither + * a way to recover nor to provide expected services. + */ + BUG(); + } + + local_irq_restore(flags); + return ret; +} +#endif diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h index 814207e7c37f..271c365973d6 100644 --- a/include/asm-generic/hyperv-tlfs.h +++ b/include/asm-generic/hyperv-tlfs.h @@ -75,6 +75,13 @@ /* AccessTscInvariantControls privilege */ #define HV_ACCESS_TSC_INVARIANT BIT(15) +/* + * This synthetic register is only accessible via the HVCALL_GET_VP_REGISTERS + * hvcall, and there is no an associated MSR on x86. + */ +#define HV_REGISTER_VSM_VP_STATUS 0x000D0003 +#define HV_VTL_MASK GENMASK(3, 0) + /* * Group B features. */ diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h index 8fe7aaab2599..85a5b8cb1702 100644 --- a/include/asm-generic/mshyperv.h +++ b/include/asm-generic/mshyperv.h @@ -315,4 +315,10 @@ static inline enum hv_isolation_type hv_get_isolation_type(void) } #endif /* CONFIG_HYPERV */ +#if IS_ENABLED(CONFIG_HYPERV_VTL_MODE) +u8 __init get_vtl(void); +#else +static inline u8 get_vtl(void) { return 0; } +#endif + #endif