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| author | Will Deacon <will@kernel.org> | 2024-05-01 18:34:00 +0200 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2024-05-08 08:05:53 +0200 |
| commit | 5053c3f0519cd4c746577e3a6a7756f7c04b03dd (patch) | |
| tree | 6adbd4db6ee17a071dfcae4325985ef15f74ddee /arch/arm64/kernel/pi/idreg-override.c | |
| parent | KVM: arm64: Fix hvhe/nvhe early alias parsing (diff) | |
| download | linux-5053c3f0519cd4c746577e3a6a7756f7c04b03dd.tar.xz linux-5053c3f0519cd4c746577e3a6a7756f7c04b03dd.zip | |
KVM: arm64: Use hVHE in pKVM by default on CPUs with VHE support
The early command line parsing treats "kvm-arm.mode=protected" as an
alias for "id_aa64mmfr1.vh=0", forcing the use of nVHE so that the host
kernel runs at EL1 with the pKVM hypervisor at EL2.
With the introduction of hVHE support in ad744e8cb346 ("arm64: Allow
arm64_sw.hvhe on command line"), the hypervisor can run using the EL2+0
translation regime. This is interesting for unusual CPUs that have VH
stuck to 1, but also because it opens the possibility of a hypervisor
"userspace" in the distant future which could be used to isolate vCPU
contexts in the hypervisor (see Marc's talk from KVM Forum 2022 [1]).
Repaint the "kvm-arm.mode=protected" alias to map to "arm64_sw.hvhe=1",
which will use hVHE on CPUs that support it and remain with nVHE
otherwise.
[1] https://www.youtube.com/watch?v=1F_Mf2j9eIo
Signed-off-by: Will Deacon <will@kernel.org>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240501163400.15838-3-will@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Diffstat (limited to '')
| -rw-r--r-- | arch/arm64/kernel/pi/idreg-override.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm64/kernel/pi/idreg-override.c b/arch/arm64/kernel/pi/idreg-override.c index 39c9253fcf23..c20549e43a77 100644 --- a/arch/arm64/kernel/pi/idreg-override.c +++ b/arch/arm64/kernel/pi/idreg-override.c @@ -210,7 +210,7 @@ static const struct { char feature[FTR_ALIAS_OPTION_LEN]; } aliases[] __initconst = { { "kvm_arm.mode=nvhe", "arm64_sw.hvhe=0 id_aa64mmfr1.vh=0" }, - { "kvm_arm.mode=protected", "id_aa64mmfr1.vh=0" }, + { "kvm_arm.mode=protected", "arm64_sw.hvhe=1" }, { "arm64.nosve", "id_aa64pfr0.sve=0" }, { "arm64.nosme", "id_aa64pfr1.sme=0" }, { "arm64.nobti", "id_aa64pfr1.bt=0" }, |