Commit 74b13d58 authored by David Brazdil's avatar David Brazdil Committed by Marc Zyngier
Browse files

KVM: arm64: Add .hyp.data section 



The hypervisor has not needed its own .data section because all globals
were either .rodata or .bss. To avoid having to initialize future
data-structures at run-time, let's introduce add a .data section to the
hypervisor.

Signed-off-by: default avatarDavid Brazdil <dbrazdil@google.com>
Signed-off-by: default avatarQuentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20250416160900.3078417-2-qperret@google.com


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 9c32cda4

arch/arm64/include/asm/sections.h

+1 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ extern char __alt_instructions[], __alt_instructions_end[]; 
extern char __hibernate_exit_text_start[], __hibernate_exit_text_end[];

extern char __hyp_idmap_text_start[], __hyp_idmap_text_end[];

extern char __hyp_text_start[], __hyp_text_end[];

extern char __hyp_data_start[], __hyp_data_end[];

extern char __hyp_rodata_start[], __hyp_rodata_end[];

extern char __hyp_reloc_begin[], __hyp_reloc_end[];

extern char __hyp_bss_start[], __hyp_bss_end[];

arch/arm64/kernel/image-vars.h

+2 −0
Original line number Diff line number Diff line
@@ -131,6 +131,8 @@ KVM_NVHE_ALIAS(__hyp_text_start); 
KVM_NVHE_ALIAS(__hyp_text_end);

KVM_NVHE_ALIAS(__hyp_bss_start);

KVM_NVHE_ALIAS(__hyp_bss_end);

KVM_NVHE_ALIAS(__hyp_data_start);

KVM_NVHE_ALIAS(__hyp_data_end);

KVM_NVHE_ALIAS(__hyp_rodata_start);

KVM_NVHE_ALIAS(__hyp_rodata_end);

arch/arm64/kernel/vmlinux.lds.S

+15 −3
Original line number Diff line number Diff line
@@ -13,7 +13,7 @@ 
	*(__kvm_ex_table)					\

	__stop___kvm_ex_table = .;



#define HYPERVISOR_DATA_SECTIONS				\

#define HYPERVISOR_RODATA_SECTIONS				\

	HYP_SECTION_NAME(.rodata) : {				\

		. = ALIGN(PAGE_SIZE);				\

		__hyp_rodata_start = .;				\
@@ -23,6 +23,15 @@ 
		__hyp_rodata_end = .;				\

	}



#define HYPERVISOR_DATA_SECTION					\

	HYP_SECTION_NAME(.data) : {				\

		. = ALIGN(PAGE_SIZE);				\

		__hyp_data_start = .;				\

		*(HYP_SECTION_NAME(.data))			\

		. = ALIGN(PAGE_SIZE);				\

		__hyp_data_end = .;				\

	}



#define HYPERVISOR_PERCPU_SECTION				\

	. = ALIGN(PAGE_SIZE);					\

	HYP_SECTION_NAME(.data..percpu) : {			\
@@ -51,7 +60,8 @@ 
#define SBSS_ALIGN			PAGE_SIZE

#else /* CONFIG_KVM */

#define HYPERVISOR_EXTABLE

#define HYPERVISOR_DATA_SECTIONS

#define HYPERVISOR_RODATA_SECTIONS

#define HYPERVISOR_DATA_SECTION

#define HYPERVISOR_PERCPU_SECTION

#define HYPERVISOR_RELOC_SECTION

#define SBSS_ALIGN			0
@@ -190,7 +200,7 @@ SECTIONS 
	/* everything from this point to __init_begin will be marked RO NX */

	RO_DATA(PAGE_SIZE)



	HYPERVISOR_DATA_SECTIONS

	HYPERVISOR_RODATA_SECTIONS



	.got : { *(.got) }

	/*
@@ -295,6 +305,8 @@ SECTIONS 
	_sdata = .;

	RW_DATA(L1_CACHE_BYTES, PAGE_SIZE, THREAD_ALIGN)



	HYPERVISOR_DATA_SECTION



	/*

	 * Data written with the MMU off but read with the MMU on requires

	 * cache lines to be invalidated, discarding up to a Cache Writeback

arch/arm64/kvm/arm.c

+7 −0
Original line number Diff line number Diff line
@@ -2604,6 +2604,13 @@ static int __init init_hyp_mode(void) 
		goto out_err;

	}



	err = create_hyp_mappings(kvm_ksym_ref(__hyp_data_start),

				  kvm_ksym_ref(__hyp_data_end), PAGE_HYP);

	if (err) {

		kvm_err("Cannot map .hyp.data section\n");

		goto out_err;

	}



	err = create_hyp_mappings(kvm_ksym_ref(__hyp_rodata_start),

				  kvm_ksym_ref(__hyp_rodata_end), PAGE_HYP_RO);

	if (err) {

arch/arm64/kvm/hyp/nvhe/hyp.lds.S

+2 −0
Original line number Diff line number Diff line
@@ -25,5 +25,7 @@ SECTIONS { 
	BEGIN_HYP_SECTION(.data..percpu)

		PERCPU_INPUT(L1_CACHE_BYTES)

	END_HYP_SECTION



	HYP_SECTION(.bss)

	HYP_SECTION(.data)

}