[PATCH v2 15/17] arm64: Make kvm-arm.mode={nvhe, protected} an alias of id_aa64mmfr1.vh=0
From: Marc Zyngier <maz@kernel.org>
Date: 2021-01-04 14:21:42
Also in:
kvmarm
Subsystem:
arm64 port (aarch64 architecture), documentation, kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Jonathan Corbet, Marc Zyngier, Oliver Upton, Linus Torvalds
Admitedly, passing id_aa64mmfr1.vh=0 on the command-line isn't that easy to understand, and it is likely that users would much prefer write "kvm-arm.mode=nvhe", or "...=protected". So here you go. This has the added advantage that we can now always honor the "kvm-arm.mode=protected" option, even when booting on a VHE system. Signed-off-by: Marc Zyngier <maz@kernel.org> --- Documentation/admin-guide/kernel-parameters.txt | 3 +++ arch/arm64/kernel/idreg-override.c | 2 ++ arch/arm64/kvm/arm.c | 3 +++ 3 files changed, 8 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index c722ec19cd00..e88e17bf5557 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt@@ -2257,6 +2257,9 @@ kvm-arm.mode= [KVM,ARM] Select one of KVM/arm64's modes of operation. + nvhe: Standard nVHE-based mode, without support for + protected guests. + protected: nVHE-based mode with support for guests whose state is kept private from the host. Not valid if the kernel is running in EL2.
diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c
index 16bc8b3b93ae..1db54878b2c4 100644
--- a/arch/arm64/kernel/idreg-override.c
+++ b/arch/arm64/kernel/idreg-override.c@@ -41,6 +41,8 @@ static const struct { const char * const alias; const char * const feature; } aliases[] __initdata = { + { "kvm-arm.mode=nvhe", "id_aa64mmfr1.vh=0" }, + { "kvm-arm.mode=protected", "id_aa64mmfr1.vh=0" }, }; static int __init find_field(const char *cmdline, const struct reg_desc *reg,
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 71a49eae9ea0..24aa57ee057c 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c@@ -1962,6 +1962,9 @@ static int __init early_kvm_mode_cfg(char *arg) return 0; } + if (strcmp(arg, "nvhe") == 0 && !WARN_ON(is_kernel_in_hyp_mode())) + return 0; + return -EINVAL; } early_param("kvm-arm.mode", early_kvm_mode_cfg);
--
2.29.2
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