From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: Hector Martin <marcan@marcan.st>, Arnd Bergmann <arnd@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Will Deacon <will@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
kernel-team@android.com
Subject: [PATCH v2 3/3] arm64: Allow nVHE impaired CPUs to boot without CONFIG_ARM64_VHE
Date: Tue, 30 Mar 2021 18:39:47 +0100 [thread overview]
Message-ID: <20210330173947.999859-4-maz@kernel.org> (raw)
In-Reply-To: <20210330173947.999859-1-maz@kernel.org>
CPUs stuck in VHE mode need some additional care if the kernel
is compiled without CONFIG_ARM64_VHE.
Treat this case as another version of a mismatched boot, and
prevent KVM from being initialised. The machine will boot in
some bizarre state, using TPIDR_EL1 instead of TPIDR_EL2, but
otherwise be functional.
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/include/asm/virt.h | 18 +++++++++++++-----
arch/arm64/kvm/va_layout.c | 9 +++++++++
2 files changed, 22 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 7379f35ae2c6..69bc4e26aa26 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -72,6 +72,11 @@ void __hyp_reset_vectors(void);
DECLARE_STATIC_KEY_FALSE(kvm_protected_mode_initialized);
+static inline bool is_kernel_in_hyp_mode(void)
+{
+ return read_sysreg(CurrentEL) == CurrentEL_EL2;
+}
+
/* Reports the availability of HYP mode */
static inline bool is_hyp_mode_available(void)
{
@@ -83,6 +88,10 @@ static inline bool is_hyp_mode_available(void)
static_branch_likely(&kvm_protected_mode_initialized))
return true;
+ /* Catch braindead CPUs */
+ if (!IS_ENABLED(CONFIG_ARM64_VHE) && is_kernel_in_hyp_mode())
+ return false;
+
return (__boot_cpu_mode[0] == BOOT_CPU_MODE_EL2 &&
__boot_cpu_mode[1] == BOOT_CPU_MODE_EL2);
}
@@ -98,12 +107,11 @@ static inline bool is_hyp_mode_mismatched(void)
static_branch_likely(&kvm_protected_mode_initialized))
return false;
- return __boot_cpu_mode[0] != __boot_cpu_mode[1];
-}
+ /* Catch braindead CPUs */
+ if (!IS_ENABLED(CONFIG_ARM64_VHE) && is_kernel_in_hyp_mode())
+ return true;
-static inline bool is_kernel_in_hyp_mode(void)
-{
- return read_sysreg(CurrentEL) == CurrentEL_EL2;
+ return __boot_cpu_mode[0] != __boot_cpu_mode[1];
}
static __always_inline bool has_vhe(void)
diff --git a/arch/arm64/kvm/va_layout.c b/arch/arm64/kvm/va_layout.c
index 978301392d67..edb048654e00 100644
--- a/arch/arm64/kvm/va_layout.c
+++ b/arch/arm64/kvm/va_layout.c
@@ -156,6 +156,9 @@ void __init kvm_update_va_mask(struct alt_instr *alt,
{
int i;
+ if (!is_hyp_mode_available())
+ return;
+
BUG_ON(nr_inst != 5);
for (i = 0; i < nr_inst; i++) {
@@ -191,6 +194,9 @@ void kvm_patch_vector_branch(struct alt_instr *alt,
u64 addr;
u32 insn;
+ if (!is_hyp_mode_available())
+ return;
+
BUG_ON(nr_inst != 4);
if (!cpus_have_const_cap(ARM64_SPECTRE_V3A) || WARN_ON_ONCE(has_vhe()))
@@ -244,6 +250,9 @@ static void generate_mov_q(u64 val, __le32 *origptr, __le32 *updptr, int nr_inst
{
u32 insn, oinsn, rd;
+ if (!is_hyp_mode_available())
+ return;
+
BUG_ON(nr_inst != 4);
/* Compute target register */
--
2.29.2
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next prev parent reply other threads:[~2021-03-30 17:41 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-30 17:39 [PATCH v2 0/3] arm64: Dealing with VHE-only CPUs Marc Zyngier
2021-03-30 17:39 ` [PATCH v2 1/3] arm64: cpufeature: Allow early filtering of feature override Marc Zyngier
2021-04-08 11:13 ` Hector Martin
2021-04-08 13:11 ` Marc Zyngier
2021-03-30 17:39 ` [PATCH v2 2/3] arm64: Cope with CPUs stuck in VHE mode Marc Zyngier
2021-04-07 21:16 ` Will Deacon
2021-03-30 17:39 ` Marc Zyngier [this message]
2021-04-07 21:18 ` [PATCH v2 3/3] arm64: Allow nVHE impaired CPUs to boot without CONFIG_ARM64_VHE Will Deacon
2021-04-08 10:31 ` Marc Zyngier
2021-04-08 10:58 ` Will Deacon
2021-04-08 13:05 ` Marc Zyngier
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