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authorOliver Upton <oliver.upton@linux.dev>2024-07-14 03:23:32 +0300
committerOliver Upton <oliver.upton@linux.dev>2024-07-14 03:23:32 +0300
commit1270dad3109770fc12c1f09f7bab4bceaf2fb829 (patch)
treec5f2df3028d18715b704576638af703382ee8fe3 /arch/arm64
parent377d0e5d7795381a4b676d7030266b4836cec53a (diff)
parenteca4ba5b6dff9b6ec03c9607ac297076f037fcfc (diff)
downloadlinux-1270dad3109770fc12c1f09f7bab4bceaf2fb829.tar.xz
Merge branch kvm-arm64/el2-kcfi into kvmarm/next
* kvm-arm64/el2-kcfi: : kCFI support in the EL2 hypervisor, courtesy of Pierre-Clément Tosi : : Enable the usage fo CONFIG_CFI_CLANG (kCFI) for hardening indirect : branches in the EL2 hypervisor. Unlike kernel support for the feature, : CFI failures at EL2 are always fatal. KVM: arm64: nVHE: Support CONFIG_CFI_CLANG at EL2 KVM: arm64: Introduce print_nvhe_hyp_panic helper arm64: Introduce esr_brk_comment, esr_is_cfi_brk KVM: arm64: VHE: Mark __hyp_call_panic __noreturn KVM: arm64: nVHE: gen-hyprel: Skip R_AARCH64_ABS32 KVM: arm64: nVHE: Simplify invalid_host_el2_vect KVM: arm64: Fix __pkvm_init_switch_pgd call ABI KVM: arm64: Fix clobbered ELR in sync abort/SError Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Diffstat (limited to 'arch/arm64')
-rw-r--r--arch/arm64/include/asm/esr.h11
-rw-r--r--arch/arm64/include/asm/kvm_hyp.h4
-rw-r--r--arch/arm64/kernel/asm-offsets.c1
-rw-r--r--arch/arm64/kernel/debug-monitors.c4
-rw-r--r--arch/arm64/kernel/traps.c8
-rw-r--r--arch/arm64/kvm/handle_exit.c24
-rw-r--r--arch/arm64/kvm/hyp/entry.S8
-rw-r--r--arch/arm64/kvm/hyp/include/hyp/switch.h5
-rw-r--r--arch/arm64/kvm/hyp/nvhe/Makefile6
-rw-r--r--arch/arm64/kvm/hyp/nvhe/gen-hyprel.c6
-rw-r--r--arch/arm64/kvm/hyp/nvhe/host.S6
-rw-r--r--arch/arm64/kvm/hyp/nvhe/hyp-init.S30
-rw-r--r--arch/arm64/kvm/hyp/nvhe/setup.c4
-rw-r--r--arch/arm64/kvm/hyp/vhe/switch.c3
14 files changed, 78 insertions, 42 deletions
diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
index 15a4be765cad..8eccf497894e 100644
--- a/arch/arm64/include/asm/esr.h
+++ b/arch/arm64/include/asm/esr.h
@@ -380,6 +380,11 @@
#ifndef __ASSEMBLY__
#include <asm/types.h>
+static inline unsigned long esr_brk_comment(unsigned long esr)
+{
+ return esr & ESR_ELx_BRK64_ISS_COMMENT_MASK;
+}
+
static inline bool esr_is_data_abort(unsigned long esr)
{
const unsigned long ec = ESR_ELx_EC(esr);
@@ -387,6 +392,12 @@ static inline bool esr_is_data_abort(unsigned long esr)
return ec == ESR_ELx_EC_DABT_LOW || ec == ESR_ELx_EC_DABT_CUR;
}
+static inline bool esr_is_cfi_brk(unsigned long esr)
+{
+ return ESR_ELx_EC(esr) == ESR_ELx_EC_BRK64 &&
+ (esr_brk_comment(esr) & ~CFI_BRK_IMM_MASK) == CFI_BRK_IMM_BASE;
+}
+
static inline bool esr_fsc_is_translation_fault(unsigned long esr)
{
/* Translation fault, level -1 */
diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
index b05bceca3385..c838309e4ec4 100644
--- a/arch/arm64/include/asm/kvm_hyp.h
+++ b/arch/arm64/include/asm/kvm_hyp.h
@@ -124,8 +124,8 @@ void __noreturn __hyp_do_panic(struct kvm_cpu_context *host_ctxt, u64 spsr,
#endif
#ifdef __KVM_NVHE_HYPERVISOR__
-void __pkvm_init_switch_pgd(phys_addr_t phys, unsigned long size,
- phys_addr_t pgd, void *sp, void *cont_fn);
+void __pkvm_init_switch_pgd(phys_addr_t pgd, unsigned long sp,
+ void (*fn)(void));
int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
unsigned long *per_cpu_base, u32 hyp_va_bits);
void __noreturn __host_enter(struct kvm_cpu_context *host_ctxt);
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index 81496083c041..27de1dddb0ab 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -128,6 +128,7 @@ int main(void)
DEFINE(VCPU_FAULT_DISR, offsetof(struct kvm_vcpu, arch.fault.disr_el1));
DEFINE(VCPU_HCR_EL2, offsetof(struct kvm_vcpu, arch.hcr_el2));
DEFINE(CPU_USER_PT_REGS, offsetof(struct kvm_cpu_context, regs));
+ DEFINE(CPU_ELR_EL2, offsetof(struct kvm_cpu_context, sys_regs[ELR_EL2]));
DEFINE(CPU_RGSR_EL1, offsetof(struct kvm_cpu_context, sys_regs[RGSR_EL1]));
DEFINE(CPU_GCR_EL1, offsetof(struct kvm_cpu_context, sys_regs[GCR_EL1]));
DEFINE(CPU_APIAKEYLO_EL1, offsetof(struct kvm_cpu_context, sys_regs[APIAKEYLO_EL1]));
diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index 64f2ecbdfe5c..024a7b245056 100644
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -312,9 +312,7 @@ static int call_break_hook(struct pt_regs *regs, unsigned long esr)
* entirely not preemptible, and we can use rcu list safely here.
*/
list_for_each_entry_rcu(hook, list, node) {
- unsigned long comment = esr & ESR_ELx_BRK64_ISS_COMMENT_MASK;
-
- if ((comment & ~hook->mask) == hook->imm)
+ if ((esr_brk_comment(esr) & ~hook->mask) == hook->imm)
fn = hook->fn;
}
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 215e6d7f2df8..9e22683aa921 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -1105,8 +1105,6 @@ static struct break_hook ubsan_break_hook = {
};
#endif
-#define esr_comment(esr) ((esr) & ESR_ELx_BRK64_ISS_COMMENT_MASK)
-
/*
* Initial handler for AArch64 BRK exceptions
* This handler only used until debug_traps_init().
@@ -1115,15 +1113,15 @@ int __init early_brk64(unsigned long addr, unsigned long esr,
struct pt_regs *regs)
{
#ifdef CONFIG_CFI_CLANG
- if ((esr_comment(esr) & ~CFI_BRK_IMM_MASK) == CFI_BRK_IMM_BASE)
+ if (esr_is_cfi_brk(esr))
return cfi_handler(regs, esr) != DBG_HOOK_HANDLED;
#endif
#ifdef CONFIG_KASAN_SW_TAGS
- if ((esr_comment(esr) & ~KASAN_BRK_MASK) == KASAN_BRK_IMM)
+ if ((esr_brk_comment(esr) & ~KASAN_BRK_MASK) == KASAN_BRK_IMM)
return kasan_handler(regs, esr) != DBG_HOOK_HANDLED;
#endif
#ifdef CONFIG_UBSAN_TRAP
- if ((esr_comment(esr) & ~UBSAN_BRK_MASK) == UBSAN_BRK_IMM)
+ if ((esr_brk_comment(esr) & ~UBSAN_BRK_MASK) == UBSAN_BRK_IMM)
return ubsan_handler(regs, esr) != DBG_HOOK_HANDLED;
#endif
return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index b037f0a0e27e..69b08ac7322d 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -411,6 +411,20 @@ void handle_exit_early(struct kvm_vcpu *vcpu, int exception_index)
kvm_handle_guest_serror(vcpu, kvm_vcpu_get_esr(vcpu));
}
+static void print_nvhe_hyp_panic(const char *name, u64 panic_addr)
+{
+ kvm_err("nVHE hyp %s at: [<%016llx>] %pB!\n", name, panic_addr,
+ (void *)(panic_addr + kaslr_offset()));
+}
+
+static void kvm_nvhe_report_cfi_failure(u64 panic_addr)
+{
+ print_nvhe_hyp_panic("CFI failure", panic_addr);
+
+ if (IS_ENABLED(CONFIG_CFI_PERMISSIVE))
+ kvm_err(" (CONFIG_CFI_PERMISSIVE ignored for hyp failures)\n");
+}
+
void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr,
u64 elr_virt, u64 elr_phys,
u64 par, uintptr_t vcpu,
@@ -423,7 +437,7 @@ void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr,
if (mode != PSR_MODE_EL2t && mode != PSR_MODE_EL2h) {
kvm_err("Invalid host exception to nVHE hyp!\n");
} else if (ESR_ELx_EC(esr) == ESR_ELx_EC_BRK64 &&
- (esr & ESR_ELx_BRK64_ISS_COMMENT_MASK) == BUG_BRK_IMM) {
+ esr_brk_comment(esr) == BUG_BRK_IMM) {
const char *file = NULL;
unsigned int line = 0;
@@ -439,11 +453,11 @@ void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr,
if (file)
kvm_err("nVHE hyp BUG at: %s:%u!\n", file, line);
else
- kvm_err("nVHE hyp BUG at: [<%016llx>] %pB!\n", panic_addr,
- (void *)(panic_addr + kaslr_offset()));
+ print_nvhe_hyp_panic("BUG", panic_addr);
+ } else if (IS_ENABLED(CONFIG_CFI_CLANG) && esr_is_cfi_brk(esr)) {
+ kvm_nvhe_report_cfi_failure(panic_addr);
} else {
- kvm_err("nVHE hyp panic at: [<%016llx>] %pB!\n", panic_addr,
- (void *)(panic_addr + kaslr_offset()));
+ print_nvhe_hyp_panic("panic", panic_addr);
}
/* Dump the nVHE hypervisor backtrace */
diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index f3aa7738b477..4433a234aa9b 100644
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -83,6 +83,14 @@ alternative_else_nop_endif
eret
sb
+SYM_INNER_LABEL(__guest_exit_restore_elr_and_panic, SYM_L_GLOBAL)
+ // x2-x29,lr: vcpu regs
+ // vcpu x0-x1 on the stack
+
+ adr_this_cpu x0, kvm_hyp_ctxt, x1
+ ldr x0, [x0, #CPU_ELR_EL2]
+ msr elr_el2, x0
+
SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL)
// x2-x29,lr: vcpu regs
// vcpu x0-x1 on the stack
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index 0c4de44534b7..1f4b87a73445 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -693,7 +693,7 @@ guest:
static inline void __kvm_unexpected_el2_exception(void)
{
- extern char __guest_exit_panic[];
+ extern char __guest_exit_restore_elr_and_panic[];
unsigned long addr, fixup;
struct kvm_exception_table_entry *entry, *end;
unsigned long elr_el2 = read_sysreg(elr_el2);
@@ -715,7 +715,8 @@ static inline void __kvm_unexpected_el2_exception(void)
}
/* Trigger a panic after restoring the hyp context. */
- write_sysreg(__guest_exit_panic, elr_el2);
+ this_cpu_ptr(&kvm_hyp_ctxt)->sys_regs[ELR_EL2] = elr_el2;
+ write_sysreg(__guest_exit_restore_elr_and_panic, elr_el2);
}
#endif /* __ARM64_KVM_HYP_SWITCH_H__ */
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index 50fa0ffb6b7e..782b34b004be 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -89,9 +89,9 @@ quiet_cmd_hyprel = HYPREL $@
quiet_cmd_hypcopy = HYPCOPY $@
cmd_hypcopy = $(OBJCOPY) --prefix-symbols=__kvm_nvhe_ $< $@
-# Remove ftrace, Shadow Call Stack, and CFI CFLAGS.
-# This is equivalent to the 'notrace', '__noscs', and '__nocfi' annotations.
-KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS) $(CC_FLAGS_CFI), $(KBUILD_CFLAGS))
+# Remove ftrace and Shadow Call Stack CFLAGS.
+# This is equivalent to the 'notrace' and '__noscs' annotations.
+KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS), $(KBUILD_CFLAGS))
# Starting from 13.0.0 llvm emits SHT_REL section '.llvm.call-graph-profile'
# when profile optimization is applied. gen-hyprel does not support SHT_REL and
# causes a build failure. Remove profile optimization flags.
diff --git a/arch/arm64/kvm/hyp/nvhe/gen-hyprel.c b/arch/arm64/kvm/hyp/nvhe/gen-hyprel.c
index 6bc88a756cb7..b63f4e1c1033 100644
--- a/arch/arm64/kvm/hyp/nvhe/gen-hyprel.c
+++ b/arch/arm64/kvm/hyp/nvhe/gen-hyprel.c
@@ -50,6 +50,9 @@
#ifndef R_AARCH64_ABS64
#define R_AARCH64_ABS64 257
#endif
+#ifndef R_AARCH64_ABS32
+#define R_AARCH64_ABS32 258
+#endif
#ifndef R_AARCH64_PREL64
#define R_AARCH64_PREL64 260
#endif
@@ -383,6 +386,9 @@ static void emit_rela_section(Elf64_Shdr *sh_rela)
case R_AARCH64_ABS64:
emit_rela_abs64(rela, sh_orig_name);
break;
+ /* Allow 32-bit absolute relocation, for kCFI type hashes. */
+ case R_AARCH64_ABS32:
+ break;
/* Allow position-relative data relocations. */
case R_AARCH64_PREL64:
case R_AARCH64_PREL32:
diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S
index 135cfb294ee5..3d610fc51f4d 100644
--- a/arch/arm64/kvm/hyp/nvhe/host.S
+++ b/arch/arm64/kvm/hyp/nvhe/host.S
@@ -197,12 +197,6 @@ SYM_FUNC_END(__host_hvc)
sub x0, sp, x0 // x0'' = sp' - x0' = (sp + x0) - sp = x0
sub sp, sp, x0 // sp'' = sp' - x0 = (sp + x0) - x0 = sp
- /* If a guest is loaded, panic out of it. */
- stp x0, x1, [sp, #-16]!
- get_loaded_vcpu x0, x1
- cbnz x0, __guest_exit_panic
- add sp, sp, #16
-
/*
* The panic may not be clean if the exception is taken before the host
* context has been saved by __host_exit or after the hyp context has
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
index 2994878d68ea..07120b37da35 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
@@ -5,6 +5,7 @@
*/
#include <linux/arm-smccc.h>
+#include <linux/cfi_types.h>
#include <linux/linkage.h>
#include <asm/alternative.h>
@@ -265,33 +266,38 @@ alternative_else_nop_endif
SYM_CODE_END(__kvm_handle_stub_hvc)
-SYM_FUNC_START(__pkvm_init_switch_pgd)
+/*
+ * void __pkvm_init_switch_pgd(phys_addr_t pgd, unsigned long sp,
+ * void (*fn)(void));
+ *
+ * SYM_TYPED_FUNC_START() allows C to call this ID-mapped function indirectly
+ * using a physical pointer without triggering a kCFI failure.
+ */
+SYM_TYPED_FUNC_START(__pkvm_init_switch_pgd)
/* Turn the MMU off */
pre_disable_mmu_workaround
- mrs x2, sctlr_el2
- bic x3, x2, #SCTLR_ELx_M
- msr sctlr_el2, x3
+ mrs x3, sctlr_el2
+ bic x4, x3, #SCTLR_ELx_M
+ msr sctlr_el2, x4
isb
tlbi alle2
/* Install the new pgtables */
- ldr x3, [x0, #NVHE_INIT_PGD_PA]
- phys_to_ttbr x4, x3
+ phys_to_ttbr x5, x0
alternative_if ARM64_HAS_CNP
- orr x4, x4, #TTBR_CNP_BIT
+ orr x5, x5, #TTBR_CNP_BIT
alternative_else_nop_endif
- msr ttbr0_el2, x4
+ msr ttbr0_el2, x5
/* Set the new stack pointer */
- ldr x0, [x0, #NVHE_INIT_STACK_HYP_VA]
- mov sp, x0
+ mov sp, x1
/* And turn the MMU back on! */
dsb nsh
isb
- set_sctlr_el2 x2
- ret x1
+ set_sctlr_el2 x3
+ ret x2
SYM_FUNC_END(__pkvm_init_switch_pgd)
.popsection
diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c
index f4350ba07b0b..174007f3fadd 100644
--- a/arch/arm64/kvm/hyp/nvhe/setup.c
+++ b/arch/arm64/kvm/hyp/nvhe/setup.c
@@ -339,7 +339,7 @@ int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
{
struct kvm_nvhe_init_params *params;
void *virt = hyp_phys_to_virt(phys);
- void (*fn)(phys_addr_t params_pa, void *finalize_fn_va);
+ typeof(__pkvm_init_switch_pgd) *fn;
int ret;
BUG_ON(kvm_check_pvm_sysreg_table());
@@ -363,7 +363,7 @@ int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
/* Jump in the idmap page to switch to the new page-tables */
params = this_cpu_ptr(&kvm_init_params);
fn = (typeof(fn))__hyp_pa(__pkvm_init_switch_pgd);
- fn(__hyp_pa(params), __pkvm_init_finalise);
+ fn(params->pgd_pa, params->stack_hyp_va, __pkvm_init_finalise);
unreachable();
}
diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c
index 88409a135a6f..7a72b3304945 100644
--- a/arch/arm64/kvm/hyp/vhe/switch.c
+++ b/arch/arm64/kvm/hyp/vhe/switch.c
@@ -437,7 +437,7 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
return ret;
}
-static void __hyp_call_panic(u64 spsr, u64 elr, u64 par)
+static void __noreturn __hyp_call_panic(u64 spsr, u64 elr, u64 par)
{
struct kvm_cpu_context *host_ctxt;
struct kvm_vcpu *vcpu;
@@ -462,7 +462,6 @@ void __noreturn hyp_panic(void)
u64 par = read_sysreg_par();
__hyp_call_panic(spsr, elr, par);
- unreachable();
}
asmlinkage void kvm_unexpected_el2_exception(void)