Commit c73bd2e0 authored by Bibo Mao's avatar Bibo Mao Committed by Xianglai Li
Browse files

LoongArch: KVM: Add Binary Translation extension support 

mainline inclusion
from mainline-v6.12-rc1
commit b67ee19a907ddb7dab8b1bb4b35659d8372bfc46
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/IAZJDO


CVE: NA

--------------------------------

Loongson Binary Translation (LBT) is used to accelerate binary translation,
which contains 4 scratch registers (scr0 to scr3), x86/ARM eflags (eflags)
and x87 fpu stack pointer (ftop).

Like FPU extension, here a lazy enabling method is used for LBT. the LBT
context is saved/restored on the vcpu context switch path.

Signed-off-by: default avatarBibo Mao <maobibo@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
Signed-off-by: default avatarXianglai Li <lixianglai@loongson.cn>
parent 3d731fef

arch/loongarch/include/asm/kvm_host.h

+9 −4
Original line number Diff line number Diff line
@@ -170,10 +170,9 @@ enum emulation_result { 
#define KVM_LARCH_FPU		(0x1 << 0)

#define KVM_LARCH_LSX		(0x1 << 1)

#define KVM_LARCH_LASX		(0x1 << 2)

#define KVM_LARCH_SWCSR_LATEST	(0x1 << 3)

#define KVM_LARCH_HWCSR_USABLE	(0x1 << 4)

#define KVM_GUEST_PMU_ENABLE	(0x1 << 5)

#define KVM_GUEST_PMU_ACTIVE	(0x1 << 6)

#define KVM_LARCH_LBT		(0x1 << 3)

#define KVM_LARCH_SWCSR_LATEST	(0x1 << 4)

#define KVM_LARCH_HWCSR_USABLE	(0x1 << 5)



struct kvm_vcpu_arch {

	/*
@@ -207,6 +206,7 @@ struct kvm_vcpu_arch { 


	/* FPU state */

	struct loongarch_fpu fpu FPU_ALIGN;

	struct loongarch_lbt lbt;



	/* CSR state */

	struct loongarch_csrs *csr;
@@ -292,6 +292,11 @@ static inline int kvm_get_pmu_num(struct kvm_vcpu_arch *arch) 
	return (arch->cpucfg[LOONGARCH_CPUCFG6] & CPUCFG6_PMNUM) >> CPUCFG6_PMNUM_SHIFT;

}



static inline bool kvm_guest_has_lbt(struct kvm_vcpu_arch *arch)

{

	return arch->cpucfg[2] & (CPUCFG2_X86BT | CPUCFG2_ARMBT | CPUCFG2_MIPSBT);

}



/* Debug: dump vcpu state */

int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu);

arch/loongarch/include/asm/kvm_vcpu.h

+6 −0
Original line number Diff line number Diff line
@@ -75,6 +75,12 @@ static inline void kvm_save_lasx(struct loongarch_fpu *fpu) { } 
static inline void kvm_restore_lasx(struct loongarch_fpu *fpu) { }

#endif



#ifdef CONFIG_CPU_HAS_LBT

int kvm_own_lbt(struct kvm_vcpu *vcpu);

#else

static inline int kvm_own_lbt(struct kvm_vcpu *vcpu) { return -EINVAL; }

#endif



void kvm_init_timer(struct kvm_vcpu *vcpu, unsigned long hz);

void kvm_save_timer(struct kvm_vcpu *vcpu);

void kvm_restore_timer(struct kvm_vcpu *vcpu);

arch/loongarch/kvm/exit.c

+9 −0
Original line number Diff line number Diff line
@@ -794,6 +794,14 @@ static int kvm_handle_lasx_disabled(struct kvm_vcpu *vcpu) 
	return RESUME_GUEST;

}



static int kvm_handle_lbt_disabled(struct kvm_vcpu *vcpu)

{

	if (kvm_own_lbt(vcpu))

		kvm_queue_exception(vcpu, EXCCODE_INE, 0);



	return RESUME_GUEST;

}



static int kvm_send_pv_ipi(struct kvm_vcpu *vcpu)

{

	unsigned int min, cpu, i;
@@ -908,6 +916,7 @@ static exit_handle_fn kvm_fault_tables[EXCCODE_INT_START] = { 
	[EXCCODE_FPDIS]			= kvm_handle_fpu_disabled,

	[EXCCODE_LSXDIS]		= kvm_handle_lsx_disabled,

	[EXCCODE_LASXDIS]		= kvm_handle_lasx_disabled,

	[EXCCODE_BTDIS]			= kvm_handle_lbt_disabled,

	[EXCCODE_GSPR]			= kvm_handle_gspr,

	[EXCCODE_HVC]			= kvm_handle_hypercall,

};

arch/loongarch/kvm/vcpu.c

+60 −1
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
#include <linux/kvm_host.h>

#include <linux/entry-kvm.h>

#include <asm/fpu.h>

#include <asm/lbt.h>

#include <asm/loongarch.h>

#include <asm/setup.h>

#include <asm/time.h>
@@ -1207,12 +1208,66 @@ int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu) 
	return 0;

}



#ifdef CONFIG_CPU_HAS_LBT

int kvm_own_lbt(struct kvm_vcpu *vcpu)

{

	if (!kvm_guest_has_lbt(&vcpu->arch))

		return -EINVAL;



	preempt_disable();

	set_csr_euen(CSR_EUEN_LBTEN);

	_restore_lbt(&vcpu->arch.lbt);

	vcpu->arch.aux_inuse |= KVM_LARCH_LBT;

	preempt_enable();



	return 0;

}



static void kvm_lose_lbt(struct kvm_vcpu *vcpu)

{

	preempt_disable();

	if (vcpu->arch.aux_inuse & KVM_LARCH_LBT) {

		_save_lbt(&vcpu->arch.lbt);

		clear_csr_euen(CSR_EUEN_LBTEN);

		vcpu->arch.aux_inuse &= ~KVM_LARCH_LBT;

	}

	preempt_enable();

}



static void kvm_check_fcsr(struct kvm_vcpu *vcpu, unsigned long fcsr)

{

	/*

	 * If TM is enabled, top register save/restore will

	 * cause lbt exception, here enable lbt in advance

	 */

	if (fcsr & FPU_CSR_TM)

		kvm_own_lbt(vcpu);

}



static void kvm_check_fcsr_alive(struct kvm_vcpu *vcpu)

{

	if (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {

		if (vcpu->arch.aux_inuse & KVM_LARCH_LBT)

			return;

		kvm_check_fcsr(vcpu, read_fcsr(LOONGARCH_FCSR0));

	}

}

#else

static inline void kvm_lose_lbt(struct kvm_vcpu *vcpu) { }

static inline void kvm_check_fcsr(struct kvm_vcpu *vcpu, unsigned long fcsr) { }

static inline void kvm_check_fcsr_alive(struct kvm_vcpu *vcpu) { }

#endif



/* Enable FPU and restore context */

void kvm_own_fpu(struct kvm_vcpu *vcpu)

{

	preempt_disable();



	/* Enable FPU */

	/*

	 * Enable FPU for guest

	 * Set FR and FRE according to guest context

	 */

	kvm_check_fcsr(vcpu, vcpu->arch.fpu.fcsr);

	set_csr_euen(CSR_EUEN_FPEN);



	kvm_restore_fpu(&vcpu->arch.fpu);
@@ -1232,6 +1287,7 @@ int kvm_own_lsx(struct kvm_vcpu *vcpu) 
	preempt_disable();



	/* Enable LSX for guest */

	kvm_check_fcsr(vcpu, vcpu->arch.fpu.fcsr);

	set_csr_euen(CSR_EUEN_LSXEN | CSR_EUEN_FPEN);

	switch (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {

	case KVM_LARCH_FPU:
@@ -1266,6 +1322,7 @@ int kvm_own_lasx(struct kvm_vcpu *vcpu) 


	preempt_disable();



	kvm_check_fcsr(vcpu, vcpu->arch.fpu.fcsr);

	set_csr_euen(CSR_EUEN_FPEN | CSR_EUEN_LSXEN | CSR_EUEN_LASXEN);

	switch (vcpu->arch.aux_inuse & (KVM_LARCH_FPU | KVM_LARCH_LSX)) {

	case KVM_LARCH_LSX:
@@ -1297,6 +1354,7 @@ void kvm_lose_fpu(struct kvm_vcpu *vcpu) 
{

	preempt_disable();



	kvm_check_fcsr_alive(vcpu);

	if (vcpu->arch.aux_inuse & KVM_LARCH_LASX) {

		kvm_save_lasx(&vcpu->arch.fpu);

		vcpu->arch.aux_inuse &= ~(KVM_LARCH_LSX | KVM_LARCH_FPU | KVM_LARCH_LASX);
@@ -1319,6 +1377,7 @@ void kvm_lose_fpu(struct kvm_vcpu *vcpu) 
		/* Disable FPU */

		clear_csr_euen(CSR_EUEN_FPEN);

	}

	kvm_lose_lbt(vcpu);



	preempt_enable();

}