From 488f94d7212b00a2ec72fb886b155f1b04c5aa98 Mon Sep 17 00:00:00 2001 From: Jintack Lim Date: Thu, 1 Dec 2016 14:32:05 -0500 Subject: KVM: arm64: Access CNTHCTL_EL2 bit fields correctly on VHE systems Current KVM world switch code is unintentionally setting wrong bits to CNTHCTL_EL2 when E2H == 1, which may allow guest OS to access physical timer. Bit positions of CNTHCTL_EL2 are changing depending on HCR_EL2.E2H bit. EL1PCEN and EL1PCTEN are 1st and 0th bits when E2H is not set, but they are 11th and 10th bits respectively when E2H is set. In fact, on VHE we only need to set those bits once, not for every world switch. This is because the host kernel runs in EL2 with HCR_EL2.TGE == 1, which makes those bits have no effect for the host kernel execution. So we just set those bits once for guests, and that's it. Signed-off-by: Jintack Lim Reviewed-by: Marc Zyngier Signed-off-by: Marc Zyngier --- arch/arm/include/asm/virt.h | 5 +++++ arch/arm/kvm/arm.c | 3 +++ 2 files changed, 8 insertions(+) (limited to 'arch/arm') diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h index a2e75b84e2ae..6dae1956c74d 100644 --- a/arch/arm/include/asm/virt.h +++ b/arch/arm/include/asm/virt.h @@ -80,6 +80,11 @@ static inline bool is_kernel_in_hyp_mode(void) return false; } +static inline bool has_vhe(void) +{ + return false; +} + /* The section containing the hypervisor idmap text */ extern char __hyp_idmap_text_start[]; extern char __hyp_idmap_text_end[]; diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 11676787ad49..9d7446456e0c 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -1099,6 +1099,9 @@ static void cpu_init_hyp_mode(void *dummy) __cpu_init_hyp_mode(pgd_ptr, hyp_stack_ptr, vector_ptr); __cpu_init_stage2(); + if (is_kernel_in_hyp_mode()) + kvm_timer_init_vhe(); + kvm_arm_init_debug(); } -- cgit v1.2.3