From 01dc9262ff5797b675c32c0c6bc682777d23de05 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Wed, 3 Mar 2021 16:45:05 +0000 Subject: KVM: arm64: Ensure I-cache isolation between vcpus of a same VM It recently became apparent that the ARMv8 architecture has interesting rules regarding attributes being used when fetching instructions if the MMU is off at Stage-1. In this situation, the CPU is allowed to fetch from the PoC and allocate into the I-cache (unless the memory is mapped with the XN attribute at Stage-2). If we transpose this to vcpus sharing a single physical CPU, it is possible for a vcpu running with its MMU off to influence another vcpu running with its MMU on, as the latter is expected to fetch from the PoU (and self-patching code doesn't flush below that level). In order to solve this, reuse the vcpu-private TLB invalidation code to apply the same policy to the I-cache, nuking it every time the vcpu runs on a physical CPU that ran another vcpu of the same VM in the past. This involve renaming __kvm_tlb_flush_local_vmid() to __kvm_flush_cpu_context(), and inserting a local i-cache invalidation there. Cc: stable@vger.kernel.org Signed-off-by: Marc Zyngier Acked-by: Will Deacon Acked-by: Catalin Marinas Link: https://lore.kernel.org/r/20210303164505.68492-1-maz@kernel.org --- arch/arm64/include/asm/kvm_asm.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/arm64/include') diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index 9c0e396dd03f..a7ab84f781f7 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -47,7 +47,7 @@ #define __KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context 2 #define __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid_ipa 3 #define __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid 4 -#define __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_local_vmid 5 +#define __KVM_HOST_SMCCC_FUNC___kvm_flush_cpu_context 5 #define __KVM_HOST_SMCCC_FUNC___kvm_timer_set_cntvoff 6 #define __KVM_HOST_SMCCC_FUNC___kvm_enable_ssbs 7 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_get_gic_config 8 @@ -183,10 +183,10 @@ DECLARE_KVM_HYP_SYM(__bp_harden_hyp_vecs); #define __bp_harden_hyp_vecs CHOOSE_HYP_SYM(__bp_harden_hyp_vecs) extern void __kvm_flush_vm_context(void); +extern void __kvm_flush_cpu_context(struct kvm_s2_mmu *mmu); extern void __kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu, phys_addr_t ipa, int level); extern void __kvm_tlb_flush_vmid(struct kvm_s2_mmu *mmu); -extern void __kvm_tlb_flush_local_vmid(struct kvm_s2_mmu *mmu); extern void __kvm_timer_set_cntvoff(u64 cntvoff); -- cgit v1.2.3