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authorLinus Torvalds <torvalds@linux-foundation.org>2021-06-29 21:21:35 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-06-29 21:21:35 +0300
commitb694011a4aec3e8df98bc59fdb78e018b09de79d (patch)
treebbbe4c92f12cfb7a50d85dbf1509e51acb19f497 /drivers/hv/hv_common.c
parentc54b245d011855ea91c5beff07f1db74143ce614 (diff)
parent7d815f4afa87f2032b650ae1bba7534b550a6b8b (diff)
downloadlinux-b694011a4aec3e8df98bc59fdb78e018b09de79d.tar.xz
Merge tag 'hyperv-next-signed-20210629' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyperv updates from Wei Liu: "Just a few minor enhancement patches and bug fixes" * tag 'hyperv-next-signed-20210629' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: PCI: hv: Add check for hyperv_initialized in init_hv_pci_drv() Drivers: hv: Move Hyper-V extended capability check to arch neutral code drivers: hv: Fix missing error code in vmbus_connect() x86/hyperv: fix logical processor creation hv_utils: Fix passing zero to 'PTR_ERR' warning scsi: storvsc: Use blk_mq_unique_tag() to generate requestIDs Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring buffer hv_balloon: Remove redundant assignment to region_start
Diffstat (limited to 'drivers/hv/hv_common.c')
-rw-r--r--drivers/hv/hv_common.c66
1 files changed, 66 insertions, 0 deletions
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
new file mode 100644
index 000000000000..7f42da98d377
--- /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 incompatible 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);