[PATCH 1/1] Drivers: hv: Move Hyper-V extended capability check to arch neutral code
From: Michael Kelley <hidden>
Date: 2021-06-02 21:37:07
The extended capability query code is currently under arch/x86, but it is architecture neutral, and is used by arch neutral code in the Hyper-V balloon driver. Hence the balloon driver fails to build on other architectures. Fix by moving the ext cap code out from arch/x86. Because it is also called from built-in architecture specific code, it can't be in a module, so the Makefile treats as built-in even when CONFIG_HYPERV is "m". Also drivers/Makefile is tweaked because this is the first occurrence of a Hyper-V file that is built-in even when CONFIG_HYPERV is "m". While here, update the hypercall status check to use the new helper function instead of open coding. No functional change. Signed-off-by: Michael Kelley <redacted> --- arch/x86/hyperv/hv_init.c | 47 --------------------------------- drivers/Makefile | 2 +- drivers/hv/Makefile | 3 +++ drivers/hv/hv_common.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 70 insertions(+), 48 deletions(-) create mode 100644 drivers/hv/hv_common.c
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index bb0ae4b..6952e21 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c@@ -614,50 +614,3 @@ bool hv_is_isolation_supported(void) return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE; } EXPORT_SYMBOL_GPL(hv_is_isolation_supported); - -/* Bit mask of the extended capability to query: see HV_EXT_CAPABILITY_xxx */ -bool hv_query_ext_cap(u64 cap_query) -{ - /* - * The address of the 'hv_extended_cap' variable will be used as an - * output parameter to the hypercall below and so it should be - * compatible with 'virt_to_phys'. Which means, it's address should be - * directly mapped. Use 'static' to keep it compatible; stack variables - * can be virtually mapped, making them imcompatible with - * 'virt_to_phys'. - * Hypercall input/output addresses should also be 8-byte aligned. - */ - static u64 hv_extended_cap __aligned(8); - static bool hv_extended_cap_queried; - u64 status; - - /* - * Querying extended capabilities is an extended hypercall. Check if the - * partition supports extended hypercall, first. - */ - if (!(ms_hyperv.priv_high & HV_ENABLE_EXTENDED_HYPERCALLS)) - return false; - - /* Extended capabilities do not change at runtime. */ - if (hv_extended_cap_queried) - return hv_extended_cap & cap_query; - - status = hv_do_hypercall(HV_EXT_CALL_QUERY_CAPABILITIES, NULL, - &hv_extended_cap); - - /* - * The query extended capabilities hypercall should not fail under - * any normal circumstances. Avoid repeatedly making the hypercall, on - * error. - */ - hv_extended_cap_queried = true; - status &= HV_HYPERCALL_RESULT_MASK; - if (status != HV_STATUS_SUCCESS) { - pr_err("Hyper-V: Extended query capabilities hypercall failed 0x%llx\n", - status); - return false; - } - - return hv_extended_cap & cap_query; -} -EXPORT_SYMBOL_GPL(hv_query_ext_cap);
diff --git a/drivers/Makefile b/drivers/Makefile
index 5a6d613..1c2e1ac 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile@@ -161,7 +161,7 @@ obj-$(CONFIG_SOUNDWIRE) += soundwire/ # Virtualization drivers obj-$(CONFIG_VIRT_DRIVERS) += virt/ -obj-$(CONFIG_HYPERV) += hv/ +obj-$(subst m,y,$(CONFIG_HYPERV)) += hv/ obj-$(CONFIG_PM_DEVFREQ) += devfreq/ obj-$(CONFIG_EXTCON) += extcon/
diff --git a/drivers/hv/Makefile b/drivers/hv/Makefile
index 94daf82..d76df5c 100644
--- a/drivers/hv/Makefile
+++ b/drivers/hv/Makefile@@ -11,3 +11,6 @@ hv_vmbus-y := vmbus_drv.o \ channel_mgmt.o ring_buffer.o hv_trace.o hv_vmbus-$(CONFIG_HYPERV_TESTING) += hv_debugfs.o hv_utils-y := hv_util.o hv_kvp.o hv_snapshot.o hv_fcopy.o hv_utils_transport.o + +# Code that must be built-in +obj-$(subst m,y,$(CONFIG_HYPERV)) += hv_common.o
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
new file mode 100644
index 0000000..f0053c7
--- /dev/null
+++ b/drivers/hv/hv_common.c@@ -0,0 +1,66 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Architecture neutral utility routines for interacting with + * Hyper-V. This file is specifically for code that must be + * built-in to the kernel image when CONFIG_HYPERV is set + * (vs. being in a module) because it is called from architecture + * specific code under arch/. + * + * Copyright (C) 2021, Microsoft, Inc. + * + * Author : Michael Kelley <mikelley@microsoft.com> + */ + +#include <linux/types.h> +#include <linux/export.h> +#include <linux/bitfield.h> +#include <asm/hyperv-tlfs.h> +#include <asm/mshyperv.h> + + +/* Bit mask of the extended capability to query: see HV_EXT_CAPABILITY_xxx */ +bool hv_query_ext_cap(u64 cap_query) +{ + /* + * The address of the 'hv_extended_cap' variable will be used as an + * output parameter to the hypercall below and so it should be + * compatible with 'virt_to_phys'. Which means, it's address should be + * directly mapped. Use 'static' to keep it compatible; stack variables + * can be virtually mapped, making them imcompatible with + * 'virt_to_phys'. + * Hypercall input/output addresses should also be 8-byte aligned. + */ + static u64 hv_extended_cap __aligned(8); + static bool hv_extended_cap_queried; + u64 status; + + /* + * Querying extended capabilities is an extended hypercall. Check if the + * partition supports extended hypercall, first. + */ + if (!(ms_hyperv.priv_high & HV_ENABLE_EXTENDED_HYPERCALLS)) + return false; + + /* Extended capabilities do not change at runtime. */ + if (hv_extended_cap_queried) + return hv_extended_cap & cap_query; + + status = hv_do_hypercall(HV_EXT_CALL_QUERY_CAPABILITIES, NULL, + &hv_extended_cap); + + /* + * The query extended capabilities hypercall should not fail under + * any normal circumstances. Avoid repeatedly making the hypercall, on + * error. + */ + hv_extended_cap_queried = true; + if (!hv_result_success(status)) { + pr_err("Hyper-V: Extended query capabilities hypercall failed 0x%llx\n", + status); + return false; + } + + return hv_extended_cap & cap_query; +} +EXPORT_SYMBOL_GPL(hv_query_ext_cap);
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1.8.3.1