From: gyutrange wlsrbwjd643@naver.com
VNCR/TLBI VA reconstruction currently uses bit 48 as the sign bit, but for 48-bit virtual addresses the correct sign bit is bit 47. Using 48 can mis-canonicalize addresses in the negative half and may cause missed invalidations.
Although VNCR_EL2 encodes other architectural fields (RESS, BADDR; see Arm ARM D24.2.206), sign_extend64() interprets its second argument as the index of the sign bit. Passing 48 prevents propagation of the canonical sign bit for 48-bit VAs.
Impact: - Incorrect canonicalization of VAs with bit47=1 - Potential stale VNCR pseudo-TLB entries after TLBI or MMU notifier - Possible incorrect translation/permissions or DoS when combined with other issues
Fixes: 667304740537 ("KVM: arm64: Mask out non-VA bits from TLBI VA* on VNCR invalidation") Cc: stable@vger.kernel.org Reported-by: DongHa Lee gap-dev@example.com Reported-by: Gyujeong Jin wlsrbwjd7232@gmail.com Reported-by: Daehyeon Ko 4ncient@example.com Reported-by: Geonha Lee leegn4a@example.com Reported-by: Hyungyu Oh dqpc_lover@example.com Reported-by: Jaewon Yang r4mbb1@example.com Signed-off-by: Gyujeong Jin wlsrbwjd7232@gmail.com --- arch/arm64/kvm/nested.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c index 77db81bae86f..eaa6dd9da086 100644 --- a/arch/arm64/kvm/nested.c +++ b/arch/arm64/kvm/nested.c @@ -1169,7 +1169,7 @@ int kvm_vcpu_allocate_vncr_tlb(struct kvm_vcpu *vcpu)
static u64 read_vncr_el2(struct kvm_vcpu *vcpu) { - return (u64)sign_extend64(__vcpu_sys_reg(vcpu, VNCR_EL2), 48); + return (u64)sign_extend64(__vcpu_sys_reg(vcpu, VNCR_EL2), 47); }
static int kvm_translate_vncr(struct kvm_vcpu *vcpu)