diff options
| author | Marc Zyngier <maz@kernel.org> | 2025-05-14 11:34:55 +0100 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2025-05-19 08:01:19 +0100 |
| commit | 73e1b621b25d7d45cebf9940cad3b377d3b94791 (patch) | |
| tree | 795a0d1f0844269a495df15268d69f913dde661a | |
| parent | 7270cc9157f474dfc46750a34c9d7defc686b2eb (diff) | |
KVM: arm64: nv: Program host's VNCR_EL2 to the fixmap address
Since we now have a way to map the guest's VNCR_EL2 on the host,
we can point the host's VNCR_EL2 to it and go full circle!
Note that we unconditionally assign the fixmap to VNCR_EL2,
irrespective of the guest's version being mapped or not. We want
to take a fault on first access, so the fixmap either contains
something guranteed to be either invalid or a guest mapping.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20250514103501.2225951-13-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
| -rw-r--r-- | arch/arm64/kvm/hyp/vhe/switch.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c index 220dee8a45e0..5eaff1ae32b2 100644 --- a/arch/arm64/kvm/hyp/vhe/switch.c +++ b/arch/arm64/kvm/hyp/vhe/switch.c @@ -48,6 +48,7 @@ DEFINE_PER_CPU(unsigned long, kvm_hyp_vector); static u64 __compute_hcr(struct kvm_vcpu *vcpu) { + u64 guest_hcr = __vcpu_sys_reg(vcpu, HCR_EL2); u64 hcr = vcpu->arch.hcr_el2; if (!vcpu_has_nv(vcpu)) @@ -70,9 +71,23 @@ static u64 __compute_hcr(struct kvm_vcpu *vcpu) write_sysreg_s(vcpu->arch.ctxt.vncr_array, SYS_VNCR_EL2); } else { host_data_clear_flag(VCPU_IN_HYP_CONTEXT); + + if (guest_hcr & HCR_NV) { + u64 va = __fix_to_virt(vncr_fixmap(smp_processor_id())); + + /* Inherit the low bits from the actual register */ + va |= __vcpu_sys_reg(vcpu, VNCR_EL2) & GENMASK(PAGE_SHIFT - 1, 0); + write_sysreg_s(va, SYS_VNCR_EL2); + + /* Force NV2 in case the guest is forgetful... */ + guest_hcr |= HCR_NV2; + } } - return hcr | (__vcpu_sys_reg(vcpu, HCR_EL2) & ~NV_HCR_GUEST_EXCLUDE); + BUG_ON(host_data_test_flag(VCPU_IN_HYP_CONTEXT) && + host_data_test_flag(L1_VNCR_MAPPED)); + + return hcr | (guest_hcr & ~NV_HCR_GUEST_EXCLUDE); } static void __activate_cptr_traps(struct kvm_vcpu *vcpu) |