Commit 9c8b91e8 authored by Jingyi Wang's avatar Jingyi Wang Committed by Zheng Zengkai
Browse files

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: default avatarZengruan Ye <yezengruan@huawei.com>
Signed-off-by: default avatarJingyi Wang <wangjingyi11@huawei.com>
Reviewed-by: default avatarKeqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent 1d939330

arch/arm64/include/asm/kvm_arm.h

+8 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <asm/types.h>



/* 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

arch/arm64/include/asm/kvm_emulate.h

+27 −0
Original line number Diff line number Diff line
@@ -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);

arch/arm64/include/asm/kvm_host.h

+8 −0
Original line number Diff line number Diff line
@@ -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__ */

arch/arm64/include/asm/virt.h

+5 −0
Original line number Diff line number Diff line
@@ -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 */

arch/arm64/kvm/arm.c

+15 −0
Original line number Diff line number Diff line
@@ -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

		 */