linux-kernel - [PATCH 01/10] Drivers: hv: vmbus: Move Hyper-V page allocator to arch neutral code

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Message-Id: <1611779025-21503-2-git-send-email-mikelley@microsoft.com>
Date:   Wed, 27 Jan 2021 12:23:36 -0800
From:   Michael Kelley <mikelley@...rosoft.com>
To:     sthemmin@...rosoft.com, kys@...rosoft.com, wei.liu@...nel.org,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, hpa@...or.com,
        daniel.lezcano@...aro.org, arnd@...db.de,
        linux-hyperv@...r.kernel.org
Cc:     mikelley@...rosoft.com, linux-kernel@...r.kernel.org,
        x86@...nel.org, linux-arch@...r.kernel.org
Subject: [PATCH 01/10] Drivers: hv: vmbus: Move Hyper-V page allocator to arch neutral code

The Hyper-V page allocator functions are implemented in an architecture
neutral way.  Move them into the architecture neutral VMbus module so
a separate implementation for ARM64 is not needed.

No functional change.

Signed-off-by: Michael Kelley <mikelley@...rosoft.com>
---
 arch/x86/hyperv/hv_init.c       | 22 ----------------------
 arch/x86/include/asm/mshyperv.h |  5 -----
 drivers/hv/hv.c                 | 36 ++++++++++++++++++++++++++++++++++++
 include/asm-generic/mshyperv.h  |  4 ++++
 4 files changed, 40 insertions(+), 27 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index e04d90a..2d1688e 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -44,28 +44,6 @@
 u32 hv_max_vp_index;
 EXPORT_SYMBOL_GPL(hv_max_vp_index);
 
-void *hv_alloc_hyperv_page(void)
-{
-	BUILD_BUG_ON(PAGE_SIZE != HV_HYP_PAGE_SIZE);
-
-	return (void *)__get_free_page(GFP_KERNEL);
-}
-EXPORT_SYMBOL_GPL(hv_alloc_hyperv_page);
-
-void *hv_alloc_hyperv_zeroed_page(void)
-{
-        BUILD_BUG_ON(PAGE_SIZE != HV_HYP_PAGE_SIZE);
-
-        return (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
-}
-EXPORT_SYMBOL_GPL(hv_alloc_hyperv_zeroed_page);
-
-void hv_free_hyperv_page(unsigned long addr)
-{
-	free_page(addr);
-}
-EXPORT_SYMBOL_GPL(hv_free_hyperv_page);
-
 static int hv_cpu_init(unsigned int cpu)
 {
 	u64 msr_vp_index;
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index ffc2899..29d0414 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -224,9 +224,6 @@ static inline struct hv_vp_assist_page *hv_get_vp_assist_page(unsigned int cpu)
 
 void __init hyperv_init(void);
 void hyperv_setup_mmu_ops(void);
-void *hv_alloc_hyperv_page(void);
-void *hv_alloc_hyperv_zeroed_page(void);
-void hv_free_hyperv_page(unsigned long addr);
 void set_hv_tscchange_cb(void (*cb)(void));
 void clear_hv_tscchange_cb(void);
 void hyperv_stop_tsc_emulation(void);
@@ -255,8 +252,6 @@ static inline void hv_set_msi_entry_from_desc(union hv_msi_entry *msi_entry,
 #else /* CONFIG_HYPERV */
 static inline void hyperv_init(void) {}
 static inline void hyperv_setup_mmu_ops(void) {}
-static inline void *hv_alloc_hyperv_page(void) { return NULL; }
-static inline void hv_free_hyperv_page(unsigned long addr) {}
 static inline void set_hv_tscchange_cb(void (*cb)(void)) {}
 static inline void clear_hv_tscchange_cb(void) {}
 static inline void hyperv_stop_tsc_emulation(void) {};
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index f202ac7..cca8d5e 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -37,6 +37,42 @@ int hv_init(void)
 }
 
 /*
+ * Functions for allocating and freeing memory with size and
+ * alignment HV_HYP_PAGE_SIZE. These functions are needed because
+ * the guest page size may not be the same as the Hyper-V page
+ * size. We depend upon kmalloc() aligning power-of-two size
+ * allocations to the allocation size boundary, so that the
+ * allocated memory appears to Hyper-V as a page of the size
+ * it expects.
+ */
+
+void *hv_alloc_hyperv_page(void)
+{
+	BUILD_BUG_ON(PAGE_SIZE <  HV_HYP_PAGE_SIZE);
+
+	if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
+		return (void *)__get_free_page(GFP_KERNEL);
+	else
+		return kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
+}
+
+void *hv_alloc_hyperv_zeroed_page(void)
+{
+	if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
+		return (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+	else
+		return kzalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
+}
+
+void hv_free_hyperv_page(unsigned long addr)
+{
+	if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
+		free_page(addr);
+	else
+		kfree((void *)addr);
+}
+
+/*
  * hv_post_message - Post a message using the hypervisor message IPC.
  *
  * This involves a hypercall.
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index c577996..762d3ac 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -114,6 +114,10 @@ static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type)
 /* Sentinel value for an uninitialized entry in hv_vp_index array */
 #define VP_INVAL	U32_MAX
 
+void *hv_alloc_hyperv_page(void);
+void *hv_alloc_hyperv_zeroed_page(void);
+void hv_free_hyperv_page(unsigned long addr);
+
 /**
  * hv_cpu_number_to_vp_number() - Map CPU to VP.
  * @cpu_number: CPU number in Linux terms
-- 
1.8.3.1