From: Will Deacon Date: Thu, 10 Nov 2022 19:02:55 +0000 (+0000) Subject: KVM: arm64: Maintain a copy of 'kvm_arm_vmid_bits' at EL2 X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=73f38ef2ae531b180685173e0923225551434fcb;p=linux.git KVM: arm64: Maintain a copy of 'kvm_arm_vmid_bits' at EL2 Sharing 'kvm_arm_vmid_bits' between EL1 and EL2 allows the host to modify the variable arbitrarily, potentially leading to all sorts of shenanians as this is used to configure the VTTBR register for the guest stage-2. In preparation for unmapping host sections entirely from EL2, maintain a copy of 'kvm_arm_vmid_bits' in the pKVM hypervisor and initialise it from the host value while it is still trusted. Tested-by: Vincent Donnefort Signed-off-by: Will Deacon Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20221110190259.26861-23-will@kernel.org --- diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h index fd99cf09972de..6797eafe7890b 100644 --- a/arch/arm64/include/asm/kvm_hyp.h +++ b/arch/arm64/include/asm/kvm_hyp.h @@ -124,4 +124,6 @@ extern u64 kvm_nvhe_sym(id_aa64mmfr1_el1_sys_val); extern u64 kvm_nvhe_sym(id_aa64mmfr2_el1_sys_val); extern unsigned long kvm_nvhe_sym(__icache_flags); +extern unsigned int kvm_nvhe_sym(kvm_arm_vmid_bits); + #endif /* __ARM64_KVM_HYP_H__ */ diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h index ae8f37f4aa8c6..31ad75da4d589 100644 --- a/arch/arm64/kernel/image-vars.h +++ b/arch/arm64/kernel/image-vars.h @@ -71,9 +71,6 @@ KVM_NVHE_ALIAS(nvhe_hyp_panic_handler); /* Vectors installed by hyp-init on reset HVC. */ KVM_NVHE_ALIAS(__hyp_stub_vectors); -/* VMID bits set by the KVM VMID allocator */ -KVM_NVHE_ALIAS(kvm_arm_vmid_bits); - /* Static keys which are set if a vGIC trap should be handled in hyp. */ KVM_NVHE_ALIAS(vgic_v2_cpuif_trap); KVM_NVHE_ALIAS(vgic_v3_cpuif_trap); diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 25467f24803dd..1d4b8122d0108 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1893,6 +1893,7 @@ static void kvm_hyp_init_symbols(void) kvm_nvhe_sym(id_aa64mmfr1_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1); kvm_nvhe_sym(id_aa64mmfr2_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64MMFR2_EL1); kvm_nvhe_sym(__icache_flags) = __icache_flags; + kvm_nvhe_sym(kvm_arm_vmid_bits) = kvm_arm_vmid_bits; } static int kvm_hyp_init_protection(u32 hyp_va_bits) diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c index 81835c2f4c5a0..ed6ceac1e8547 100644 --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c @@ -15,6 +15,9 @@ /* Used by icache_is_vpipt(). */ unsigned long __icache_flags; +/* Used by kvm_get_vttbr(). */ +unsigned int kvm_arm_vmid_bits; + /* * Set trap register values based on features in ID_AA64PFR0. */