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ARM: KVM: Cleanup exception injection 

David Binderman reported that the exception injection code had a
couple of unused variables lingering around.

Upon examination, it looked like this code could do with an
anticipated spring cleaning, which amounts to deduplicating
the CPSR/SPSR update, and making it look a bit more like
the architecture spec.

The spurious variables are removed in the process.

Reported-by: David Binderman <dcb314@hotmail.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Marc Zyngier 2015-12-14 17:58:33 +00:00
parent 3ffa75cd18
commit e078ef8151
1 changed files with 38 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

74
arch/arm/kvm/emulate.c
View File

@ -275,6 +275,40 @@ static u32 exc_vector_base(struct kvm_vcpu *vcpu)
return vbar;
}
/*
* Switch to an exception mode, updating both CPSR and SPSR. Follow
* the logic described in AArch32.EnterMode() from the ARMv8 ARM.
*/
static void kvm_update_psr(struct kvm_vcpu *vcpu, unsigned long mode)
{
unsigned long cpsr = *vcpu_cpsr(vcpu);
u32 sctlr = vcpu->arch.cp15[c1_SCTLR];
*vcpu_cpsr(vcpu) = (cpsr & ~MODE_MASK) | mode;
switch (mode) {
case FIQ_MODE:
*vcpu_cpsr(vcpu) |= PSR_F_BIT;
/* Fall through */
case ABT_MODE:
case IRQ_MODE:
*vcpu_cpsr(vcpu) |= PSR_A_BIT;
/* Fall through */
default:
*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 the mode banked copies */
*vcpu_spsr(vcpu) = cpsr;
}
/**
* kvm_inject_undefined - inject an undefined exception into the guest
* @vcpu: The VCPU to receive the undefined exception
@ -286,29 +320,13 @@ static u32 exc_vector_base(struct kvm_vcpu *vcpu)
*/
void kvm_inject_undefined(struct kvm_vcpu *vcpu)
{
unsigned long new_lr_value;
unsigned long new_spsr_value;
unsigned long 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;
kvm_update_psr(vcpu, UND_MODE);
*vcpu_reg(vcpu, 14) = *vcpu_pc(vcpu) - return_offset;
/* Branch to exception vector */
*vcpu_pc(vcpu) = exc_vector_base(vcpu) + vect_offset;
@ -320,30 +338,14 @@ void kvm_inject_undefined(struct kvm_vcpu *vcpu)
*/
static void inject_abt(struct kvm_vcpu *vcpu, bool is_pabt, unsigned long addr)
{
unsigned long new_lr_value;
unsigned long new_spsr_value;
unsigned long 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;
kvm_update_psr(vcpu, ABT_MODE);
*vcpu_reg(vcpu, 14) = *vcpu_pc(vcpu) + return_offset;
if (is_pabt)
vect_offset = 12;