[PATCH v2 09/24] kvm: arm64: Add .hyp.data..ro_after_init ELF section
From: David Brazdil <hidden>
Date: 2020-11-16 20:44:11
Also in:
kvmarm, lkml
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
Add rules for renaming the .data..ro_after_init ELF section in KVM nVHE object files to .hyp.data..ro_after_init, linking it into the kernel and mapping it in hyp at runtime. The section is RW to the host, then mapped RO in hyp. The expectation is that the host populates the variables in the section and they are never changed by hyp afterwards. Signed-off-by: David Brazdil <redacted> --- arch/arm64/include/asm/sections.h | 1 + arch/arm64/kernel/vmlinux.lds.S | 10 ++++++++++ arch/arm64/kvm/arm.c | 8 ++++++++ arch/arm64/kvm/hyp/nvhe/hyp.lds.S | 1 + 4 files changed, 20 insertions(+)
diff --git a/arch/arm64/include/asm/sections.h b/arch/arm64/include/asm/sections.h
index 3994169985ef..8ff579361731 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_ro_after_init_start[], __hyp_data_ro_after_init_end[]; extern char __idmap_text_start[], __idmap_text_end[]; extern char __initdata_begin[], __initdata_end[]; extern char __inittext_begin[], __inittext_end[];
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 1bda604f4c70..4382b5d0645d 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S@@ -30,6 +30,13 @@ jiffies = jiffies_64; *(__kvm_ex_table) \ __stop___kvm_ex_table = .; +#define HYPERVISOR_DATA_SECTIONS \ + HYP_SECTION_NAME(.data..ro_after_init) : { \ + __hyp_data_ro_after_init_start = .; \ + *(HYP_SECTION_NAME(.data..ro_after_init)) \ + __hyp_data_ro_after_init_end = .; \ + } + #define HYPERVISOR_PERCPU_SECTION \ . = ALIGN(PAGE_SIZE); \ HYP_SECTION_NAME(.data..percpu) : { \
@@ -37,6 +44,7 @@ jiffies = jiffies_64; } #else /* CONFIG_KVM */ #define HYPERVISOR_EXTABLE +#define HYPERVISOR_DATA_SECTIONS #define HYPERVISOR_PERCPU_SECTION #endif
@@ -234,6 +242,8 @@ SECTIONS _sdata = .; RW_DATA(L1_CACHE_BYTES, PAGE_SIZE, THREAD_ALIGN) + HYPERVISOR_DATA_SECTIONS + /* * 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 4838556920fb..97af6c285f84 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c@@ -1620,6 +1620,14 @@ static int init_hyp_mode(void) goto out_err; } + err = create_hyp_mappings(kvm_ksym_ref(__hyp_data_ro_after_init_start), + kvm_ksym_ref(__hyp_data_ro_after_init_end), + PAGE_HYP_RO); + if (err) { + kvm_err("Cannot map .hyp.data..ro_after_init section\n"); + goto out_err; + } + err = create_hyp_mappings(kvm_ksym_ref(__start_rodata), kvm_ksym_ref(__end_rodata), 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 bb2d986ff696..5d76ff2ba63e 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp.lds.S
+++ b/arch/arm64/kvm/hyp/nvhe/hyp.lds.S@@ -16,4 +16,5 @@ SECTIONS { HYP_SECTION_NAME(.data..percpu) : { PERCPU_INPUT(L1_CACHE_BYTES) } + HYP_SECTION(.data..ro_after_init) }
--
2.29.2.299.gdc1121823c-goog
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