From dae7d6cca27e5871335e7480ea24cbf8777fcc37 Mon Sep 17 00:00:00 2001 From: Jingyi Wang Date: Thu, 15 Jul 2021 11:33:47 +0800 Subject: [PATCH] KVM: arm64: Make use of TWED feature virt inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I40FGG CVE: NA ----------------------------- For HCR_EL2, TWEDEn(bit[59]) decides whether TWED is enabled, and when the configurable delay is enabled, TWEDEL (bits[63:60]) encodes the minimum delay in taking a trap of WFE caused by the TWE bit in this register as 2^(TWEDEL + 8) cycles. We use two kernel parameters "twed_enable" and "twedel" to configure the register. Signed-off-by: Zengruan Ye Signed-off-by: Jingyi Wang Reviewed-by: Keqian Zhu Signed-off-by: Zheng Zengkai --- arch/arm64/include/asm/kvm_arm.h | 8 ++++++++ arch/arm64/include/asm/kvm_emulate.h | 27 +++++++++++++++++++++++++++ arch/arm64/include/asm/kvm_host.h | 8 ++++++++ arch/arm64/include/asm/virt.h | 5 +++++ arch/arm64/kvm/arm.c | 15 +++++++++++++++ 5 files changed, 63 insertions(+) diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h index 395cb22d9f7d..b2d5d24cbeac 100644 --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -12,6 +12,7 @@ #include /* Hyp Configuration Register (HCR) bits */ +#define HCR_TWEDEN (UL(1) << 59) #define HCR_ATA (UL(1) << 56) #define HCR_FWB (UL(1) << 46) #define HCR_API (UL(1) << 41) @@ -56,6 +57,13 @@ #define HCR_SWIO (UL(1) << 1) #define HCR_VM (UL(1) << 0) +#ifdef CONFIG_ARM64_TWED +#define HCR_TWEDEL_SHIFT 60 +#define HCR_TWEDEL_MAX (UL(0xf)) +#define HCR_TWEDEL_MASK (HCR_TWEDEL_MAX << HCR_TWEDEL_SHIFT) +#define HCR_TWEDEL (UL(1) << HCR_TWEDEL_SHIFT) +#endif + /* * The bits we set in HCR: * TLOR: Trap LORegion register accesses diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 472122d731b0..87096320426e 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -102,6 +102,33 @@ static inline void vcpu_set_wfx_traps(struct kvm_vcpu *vcpu) vcpu->arch.hcr_el2 |= HCR_TWI; } +#ifdef CONFIG_ARM64_TWED +static inline void vcpu_twed_enable(struct kvm_vcpu *vcpu) +{ + vcpu->arch.hcr_el2 |= HCR_TWEDEN; +} + +static inline void vcpu_twed_disable(struct kvm_vcpu *vcpu) +{ + vcpu->arch.hcr_el2 &= ~HCR_TWEDEN; +} + +static inline void vcpu_set_twed(struct kvm_vcpu *vcpu) +{ + u64 delay = (u64)twedel; + + if (delay > HCR_TWEDEL_MAX) + delay = HCR_TWEDEL_MAX; + + vcpu->arch.hcr_el2 &= ~HCR_TWEDEL_MASK; + vcpu->arch.hcr_el2 |= (delay << HCR_TWEDEL_SHIFT); +} +#else +static inline void vcpu_twed_enable(struct kvm_vcpu *vcpu) {}; +static inline void vcpu_twed_disable(struct kvm_vcpu *vcpu) {}; +static inline void vcpu_set_twed(struct kvm_vcpu *vcpu) {}; +#endif + static inline void vcpu_ptrauth_enable(struct kvm_vcpu *vcpu) { vcpu->arch.hcr_el2 |= (HCR_API | HCR_APK); diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 50a297e23b4b..a2a61bb37b22 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -699,4 +699,12 @@ bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu); #define kvm_arm_vcpu_sve_finalized(vcpu) \ ((vcpu)->arch.flags & KVM_ARM64_VCPU_SVE_FINALIZED) +#ifdef CONFIG_ARM64_TWED +#define use_twed() (has_twed() && twed_enable) +extern bool twed_enable; +extern unsigned int twedel; +#else +#define use_twed() (false) +#endif + #endif /* __ARM64_KVM_HOST_H__ */ diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h index 6069be50baf9..412b9ac95396 100644 --- a/arch/arm64/include/asm/virt.h +++ b/arch/arm64/include/asm/virt.h @@ -97,6 +97,11 @@ static __always_inline bool has_vhe(void) return cpus_have_final_cap(ARM64_HAS_VIRT_HOST_EXTN); } +static __always_inline bool has_twed(void) +{ + return cpus_have_const_cap(ARM64_HAS_TWED); +} + #endif /* __ASSEMBLY__ */ #endif /* ! __ASM__VIRT_H */ diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 046208118a35..6c6d51ab8730 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -61,6 +61,14 @@ static bool vgic_present; static DEFINE_PER_CPU(unsigned char, kvm_arm_hardware_enabled); DEFINE_STATIC_KEY_FALSE(userspace_irqchip_in_use); +#ifdef CONFIG_ARM64_TWED +bool twed_enable = false; +module_param(twed_enable, bool, S_IRUGO | S_IWUSR); + +unsigned int twedel = 0; +module_param(twedel, uint, S_IRUGO | S_IWUSR); +#endif + int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu) { return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE; @@ -818,6 +826,13 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) kvm_arm_setup_debug(vcpu); + if (use_twed()) { + vcpu_twed_enable(vcpu); + vcpu_set_twed(vcpu); + } else { + vcpu_twed_disable(vcpu); + } + /************************************************************** * Enter the guest */ -- GitLab