From 8b0b98ebf34d6e6ad68a27109f78f2e153187737 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 20 Feb 2025 13:49:05 +0000 Subject: [PATCH] KVM: arm64: Advertise FEAT_ECV when possible We can advertise support for FEAT_ECV if supported on the HW as long as we limit it to the basic trap bits, and not advertise CNTPOFF_EL2 support, even if the host has it (the short story being that CNTPOFF_EL2 is not virtualisable). Signed-off-by: Marc Zyngier Reviewed-by: Joey Gouly Link: https://lore.kernel.org/r/20250220134907.554085-13-maz@kernel.org Signed-off-by: Oliver Upton --- arch/arm64/kvm/nested.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c index 933dc3acac5f..d55c296fcb27 100644 --- a/arch/arm64/kvm/nested.c +++ b/arch/arm64/kvm/nested.c @@ -848,14 +848,16 @@ u64 limit_nv_id_reg(struct kvm *kvm, u32 reg, u64 val) break; case SYS_ID_AA64MMFR0_EL1: - /* Hide ECV, ExS, Secure Memory */ - val &= ~(ID_AA64MMFR0_EL1_ECV | - ID_AA64MMFR0_EL1_EXS | + /* Hide ExS, Secure Memory */ + val &= ~(ID_AA64MMFR0_EL1_EXS | ID_AA64MMFR0_EL1_TGRAN4_2 | ID_AA64MMFR0_EL1_TGRAN16_2 | ID_AA64MMFR0_EL1_TGRAN64_2 | ID_AA64MMFR0_EL1_SNSMEM); + /* Hide CNTPOFF if present */ + val = ID_REG_LIMIT_FIELD_ENUM(val, ID_AA64MMFR0_EL1, ECV, IMP); + /* Disallow unsupported S2 page sizes */ switch (PAGE_SIZE) { case SZ_64K: -- 2.25.1