Commit a4d7e8ae authored by Michael Kelley's avatar Michael Kelley Committed by Wei Liu
Browse files

Drivers: hv: Move Hyper-V extended capability check to arch neutral code 



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: default avatarMichael Kelley <mikelley@microsoft.com>
Reviewed-by: default avatarSunil Muthuswamy <sunilmut@microsoft.com>
Link: https://lore.kernel.org/r/1622669804-2016-1-git-send-email-mikelley@microsoft.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
parent 9de6655c

arch/x86/hyperv/hv_init.c

+0 −47
Original line number Diff line number Diff line
@@ -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);

drivers/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -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/

drivers/hv/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -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

drivers/hv/hv_common.c

0 → 100644
+66 −0
Original line number Diff line number Diff line 
// 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);