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Code

KVM: arm64: Add .hyp.data section

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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: David Brazdil <dbrazdil@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20250416160900.3078417-2-qperret@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
David Brazdil 2025-04-16 16:08:57 +00:00 committed by Marc Zyngier
parent 9c32cda43e
commit 74b13d5816
7 changed files with 32 additions and 3 deletions
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1
arch/arm64/include/asm/sections.h
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@ -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[];

2
arch/arm64/kernel/image-vars.h
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@ -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);

18
arch/arm64/kernel/vmlinux.lds.S
View File

@ -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

7
arch/arm64/kvm/arm.c
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@ -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) {

2
arch/arm64/kvm/hyp/nvhe/hyp.lds.S
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@ -25,5 +25,7 @@ SECTIONS {
BEGIN_HYP_SECTION(.data..percpu)
PERCPU_INPUT(L1_CACHE_BYTES)
END_HYP_SECTION
HYP_SECTION(.bss)
HYP_SECTION(.data)
}

4
arch/arm64/kvm/hyp/nvhe/setup.c
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@ -119,6 +119,10 @@ static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size,
if (ret)
return ret;
ret = pkvm_create_mappings(__hyp_data_start, __hyp_data_end, PAGE_HYP);
if (ret)
return ret;
ret = pkvm_create_mappings(__hyp_rodata_start, __hyp_rodata_end, PAGE_HYP_RO);
if (ret)
return ret;

1
arch/arm64/kvm/pkvm.c
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@ -262,6 +262,7 @@ static int __init finalize_pkvm(void)
* at, which would end badly once inaccessible.
*/
kmemleak_free_part(__hyp_bss_start, __hyp_bss_end - __hyp_bss_start);
kmemleak_free_part(__hyp_data_start, __hyp_data_end - __hyp_data_start);
kmemleak_free_part(__hyp_rodata_start, __hyp_rodata_end - __hyp_rodata_start);
kmemleak_free_part_phys(hyp_mem_base, hyp_mem_size);