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: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Link: https://lore.kernel.org/r/1622669804-2016-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>

1 files changed, 0 insertions, 47 deletions

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index bb0ae4b5c00f..6952e219cba3 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);