x86: hv: Add function to allocate zeroed page for Hyper-V (fa36dcdf) · Commits · 戴 / test

Hyper-V assumes page size to be 4K. While this assumption holds true on x86 architecture, it might not be true for ARM64 architecture. Hence define hyper-v specific function to allocate a zeroed page which can have a different implementation on ARM64 architecture to handle the conflict between hyper-v's assumed page size and actual guest page size. Signed-off-by:

Himadri Pandya <himadri18.07@gmail.com> Reviewed-by:

Michael Kelley <mikelley@microsoft.com> Signed-off-by:

Sasha Levin <sashal@kernel.org>

arch/x86/hyperv/hv_init.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -45,6 +45,14 @@ void *hv_alloc_hyperv_page(void)
		}
		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);

arch/x86/include/asm/mshyperv.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -219,6 +219,7 @@ 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 hyperv_reenlightenment_intr(struct pt_regs *regs);
		void set_hv_tscchange_cb(void (*cb)(void));

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