diff options
Diffstat (limited to 'arch/arm/kvm/emulate.c')
| -rw-r--r-- | arch/arm/kvm/emulate.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/arch/arm/kvm/emulate.c b/arch/arm/kvm/emulate.c index 3eadc25e95de..d61450ac6665 100644 --- a/arch/arm/kvm/emulate.c +++ b/arch/arm/kvm/emulate.c @@ -16,7 +16,13 @@ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ +#include <linux/mm.h> +#include <linux/kvm_host.h> +#include <asm/kvm_arm.h> #include <asm/kvm_emulate.h> +#include <trace/events/kvm.h> + +#include "trace.h" #define VCPU_NR_MODES 6 #define VCPU_REG_OFFSET_USR 0 @@ -153,3 +159,215 @@ u32 *vcpu_spsr(struct kvm_vcpu *vcpu) BUG(); } } + +/** + * kvm_handle_wfi - handle a wait-for-interrupts instruction executed by a guest + * @vcpu: the vcpu pointer + * @run: the kvm_run structure pointer + * + * Simply sets the wait_for_interrupts flag on the vcpu structure, which will + * halt execution of world-switches and schedule other host processes until + * there is an incoming IRQ or FIQ to the VM. + */ +int kvm_handle_wfi(struct kvm_vcpu *vcpu, struct kvm_run *run) +{ + trace_kvm_wfi(*vcpu_pc(vcpu)); + kvm_vcpu_block(vcpu); + return 1; +} + +/** + * adjust_itstate - adjust ITSTATE when emulating instructions in IT-block + * @vcpu: The VCPU pointer + * + * When exceptions occur while instructions are executed in Thumb IF-THEN + * blocks, the ITSTATE field of the CPSR is not advanved (updated), so we have + * to do this little bit of work manually. The fields map like this: + * + * IT[7:0] -> CPSR[26:25],CPSR[15:10] + */ +static void kvm_adjust_itstate(struct kvm_vcpu *vcpu) +{ + unsigned long itbits, cond; + unsigned long cpsr = *vcpu_cpsr(vcpu); + bool is_arm = !(cpsr & PSR_T_BIT); + + BUG_ON(is_arm && (cpsr & PSR_IT_MASK)); + + if (!(cpsr & PSR_IT_MASK)) + return; + + cond = (cpsr & 0xe000) >> 13; + itbits = (cpsr & 0x1c00) >> (10 - 2); + itbits |= (cpsr & (0x3 << 25)) >> 25; + + /* Perform ITAdvance (see page A-52 in ARM DDI 0406C) */ + if ((itbits & 0x7) == 0) + itbits = cond = 0; + else + itbits = (itbits << 1) & 0x1f; + + cpsr &= ~PSR_IT_MASK; + cpsr |= cond << 13; + cpsr |= (itbits & 0x1c) << (10 - 2); + cpsr |= (itbits & 0x3) << 25; + *vcpu_cpsr(vcpu) = cpsr; +} + +/** + * kvm_skip_instr - skip a trapped instruction and proceed to the next + * @vcpu: The vcpu pointer + */ +void kvm_skip_instr(struct kvm_vcpu *vcpu, bool is_wide_instr) +{ + bool is_thumb; + + is_thumb = !!(*vcpu_cpsr(vcpu) & PSR_T_BIT); + if (is_thumb && !is_wide_instr) + *vcpu_pc(vcpu) += 2; + else + *vcpu_pc(vcpu) += 4; + kvm_adjust_itstate(vcpu); +} + + +/****************************************************************************** + * Inject exceptions into the guest + */ + +static u32 exc_vector_base(struct kvm_vcpu *vcpu) +{ + u32 sctlr = vcpu->arch.cp15[c1_SCTLR]; + u32 vbar = vcpu->arch.cp15[c12_VBAR]; + + if (sctlr & SCTLR_V) + return 0xffff0000; + else /* always have security exceptions */ + return vbar; +} + +/** + * kvm_inject_undefined - inject an undefined exception into the guest + * @vcpu: The VCPU to receive the undefined exception + * + * It is assumed that this code is called from the VCPU thread and that the + * VCPU therefore is not currently executing guest code. + * + * Modelled after TakeUndefInstrException() pseudocode. + */ +void kvm_inject_undefined(struct kvm_vcpu *vcpu) +{ + u32 new_lr_value; + u32 new_spsr_value; + u32 cpsr = *vcpu_cpsr(vcpu); + u32 sctlr = vcpu->arch.cp15[c1_SCTLR]; + bool is_thumb = (cpsr & PSR_T_BIT); + u32 vect_offset = 4; + u32 return_offset = (is_thumb) ? 2 : 4; + + new_spsr_value = cpsr; + new_lr_value = *vcpu_pc(vcpu) - return_offset; + + *vcpu_cpsr(vcpu) = (cpsr & ~MODE_MASK) | UND_MODE; + *vcpu_cpsr(vcpu) |= PSR_I_BIT; + *vcpu_cpsr(vcpu) &= ~(PSR_IT_MASK | PSR_J_BIT | PSR_E_BIT | PSR_T_BIT); + + if (sctlr & SCTLR_TE) + *vcpu_cpsr(vcpu) |= PSR_T_BIT; + if (sctlr & SCTLR_EE) + *vcpu_cpsr(vcpu) |= PSR_E_BIT; + + /* Note: These now point to UND banked copies */ + *vcpu_spsr(vcpu) = cpsr; + *vcpu_reg(vcpu, 14) = new_lr_value; + + /* Branch to exception vector */ + *vcpu_pc(vcpu) = exc_vector_base(vcpu) + vect_offset; +} + +/* + * Modelled after TakeDataAbortException() and TakePrefetchAbortException + * pseudocode. + */ +static void inject_abt(struct kvm_vcpu *vcpu, bool is_pabt, unsigned long addr) +{ + u32 new_lr_value; + u32 new_spsr_value; + u32 cpsr = *vcpu_cpsr(vcpu); + u32 sctlr = vcpu->arch.cp15[c1_SCTLR]; + bool is_thumb = (cpsr & PSR_T_BIT); + u32 vect_offset; + u32 return_offset = (is_thumb) ? 4 : 0; + bool is_lpae; + + new_spsr_value = cpsr; + new_lr_value = *vcpu_pc(vcpu) + return_offset; + + *vcpu_cpsr(vcpu) = (cpsr & ~MODE_MASK) | ABT_MODE; + *vcpu_cpsr(vcpu) |= PSR_I_BIT | PSR_A_BIT; + *vcpu_cpsr(vcpu) &= ~(PSR_IT_MASK | PSR_J_BIT | PSR_E_BIT | PSR_T_BIT); + + if (sctlr & SCTLR_TE) + *vcpu_cpsr(vcpu) |= PSR_T_BIT; + if (sctlr & SCTLR_EE) + *vcpu_cpsr(vcpu) |= PSR_E_BIT; + + /* Note: These now point to ABT banked copies */ + *vcpu_spsr(vcpu) = cpsr; + *vcpu_reg(vcpu, 14) = new_lr_value; + + if (is_pabt) + vect_offset = 12; + else + vect_offset = 16; + + /* Branch to exception vector */ + *vcpu_pc(vcpu) = exc_vector_base(vcpu) + vect_offset; + + if (is_pabt) { + /* Set DFAR and DFSR */ + vcpu->arch.cp15[c6_IFAR] = addr; + is_lpae = (vcpu->arch.cp15[c2_TTBCR] >> 31); + /* Always give debug fault for now - should give guest a clue */ + if (is_lpae) + vcpu->arch.cp15[c5_IFSR] = 1 << 9 | 0x22; + else + vcpu->arch.cp15[c5_IFSR] = 2; + } else { /* !iabt */ + /* Set DFAR and DFSR */ + vcpu->arch.cp15[c6_DFAR] = addr; + is_lpae = (vcpu->arch.cp15[c2_TTBCR] >> 31); + /* Always give debug fault for now - should give guest a clue */ + if (is_lpae) + vcpu->arch.cp15[c5_DFSR] = 1 << 9 | 0x22; + else + vcpu->arch.cp15[c5_DFSR] = 2; + } + +} + +/** + * kvm_inject_dabt - inject a data abort into the guest + * @vcpu: The VCPU to receive the undefined exception + * @addr: The address to report in the DFAR + * + * It is assumed that this code is called from the VCPU thread and that the + * VCPU therefore is not currently executing guest code. + */ +void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr) +{ + inject_abt(vcpu, false, addr); +} + +/** + * kvm_inject_pabt - inject a prefetch abort into the guest + * @vcpu: The VCPU to receive the undefined exception + * @addr: The address to report in the DFAR + * + * It is assumed that this code is called from the VCPU thread and that the + * VCPU therefore is not currently executing guest code. + */ +void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr) +{ + inject_abt(vcpu, true, addr); +} |