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Message-ID: <20250225015327.3708420-2-qperret@google.com>
Date: Tue, 25 Feb 2025 01:53:24 +0000
From: Quentin Perret <qperret@...gle.com>
To: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>,
Joey Gouly <joey.gouly@....com>, Suzuki K Poulose <suzuki.poulose@....com>,
Zenghui Yu <yuzenghui@...wei.com>, Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>
Cc: linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
linux-kernel@...r.kernel.org, qperret@...gle.com
Subject: [PATCH v2 1/4] KVM: arm64: Add .hyp.data section
From: David Brazdil <dbrazdil@...gle.com>
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@...gle.com>
Signed-off-by: Quentin Perret <qperret@...gle.com>
---
arch/arm64/include/asm/sections.h | 1 +
arch/arm64/kernel/image-vars.h | 2 ++
arch/arm64/kernel/vmlinux.lds.S | 18 +++++++++++++++---
arch/arm64/kvm/arm.c | 7 +++++++
arch/arm64/kvm/hyp/nvhe/hyp.lds.S | 2 ++
arch/arm64/kvm/hyp/nvhe/setup.c | 4 ++++
arch/arm64/kvm/pkvm.c | 1 +
7 files changed, 32 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/sections.h b/arch/arm64/include/asm/sections.h
index 40971ac1303f..51b0d594239e 100644
--- a/arch/arm64/include/asm/sections.h
+++ b/arch/arm64/include/asm/sections.h
@@ -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[];
diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index ef3a69cc398e..7c675e61ae58 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -135,6 +135,8 @@ 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);
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index e73326bd3ff7..7c770053f072 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -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
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index b8e55a441282..94d23b901b66 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -2568,6 +2568,13 @@ 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) {
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp.lds.S b/arch/arm64/kvm/hyp/nvhe/hyp.lds.S
index f4562f417d3f..d724f6d69302 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp.lds.S
+++ b/arch/arm64/kvm/hyp/nvhe/hyp.lds.S
@@ -25,5 +25,7 @@ SECTIONS {
BEGIN_HYP_SECTION(.data..percpu)
PERCPU_INPUT(L1_CACHE_BYTES)
END_HYP_SECTION
+
HYP_SECTION(.bss)
+ HYP_SECTION(.data)
}
diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c
index d62bcb5634a2..46d9bd04348f 100644
--- a/arch/arm64/kvm/hyp/nvhe/setup.c
+++ b/arch/arm64/kvm/hyp/nvhe/setup.c
@@ -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;
diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
index 930b677eb9b0..5a75f9554e57 100644
--- a/arch/arm64/kvm/pkvm.c
+++ b/arch/arm64/kvm/pkvm.c
@@ -259,6 +259,7 @@ 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);
--
2.48.1.658.g4767266eb4-goog
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