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arm64: KVM: add SGI generation register emulation 

While the generation of a (virtual) inter-processor interrupt (SGI)
on a GICv2 works by writing to a MMIO register, GICv3 uses the system
register ICC_SGI1R_EL1 to trigger them.
Add a trap handler function that calls the new SGI register handler
in the GICv3 code. As ICC_SRE_EL1.SRE at this point is still always 0,
this will not trap yet, but will only be used later when all the data
structures have been initialized properly.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
This commit is contained in:
Andre Przywara 2014-06-03 10:13:13 +02:00 committed by Christoffer Dall
parent 7e5802781c
commit 6d52f35af1
3 changed files with 139 additions and 0 deletions
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27
arch/arm64/kvm/sys_regs.c
View File

@ -165,6 +165,27 @@ static bool access_sctlr(struct kvm_vcpu *vcpu,
return true;
}
/*
* Trap handler for the GICv3 SGI generation system register.
* Forward the request to the VGIC emulation.
* The cp15_64 code makes sure this automatically works
* for both AArch64 and AArch32 accesses.
*/
static bool access_gic_sgi(struct kvm_vcpu *vcpu,
const struct sys_reg_params *p,
const struct sys_reg_desc *r)
{
u64 val;
if (!p->is_write)
return read_from_write_only(vcpu, p);
val = *vcpu_reg(vcpu, p->Rt);
vgic_v3_dispatch_sgi(vcpu, val);
return true;
}
static bool trap_raz_wi(struct kvm_vcpu *vcpu,
const struct sys_reg_params *p,
const struct sys_reg_desc *r)
@ -434,6 +455,9 @@ static const struct sys_reg_desc sys_reg_descs[] = {
{ Op0(0b11), Op1(0b000), CRn(0b1100), CRm(0b0000), Op2(0b000),
NULL, reset_val, VBAR_EL1, 0 },
/* ICC_SGI1R_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b1100), CRm(0b1011), Op2(0b101),
access_gic_sgi },
/* ICC_SRE_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b1100), CRm(0b1100), Op2(0b101),
trap_raz_wi },
@ -666,6 +690,8 @@ static const struct sys_reg_desc cp14_64_regs[] = {
* register).
*/
static const struct sys_reg_desc cp15_regs[] = {
{ Op1( 0), CRn( 0), CRm(12), Op2( 0), access_gic_sgi },
{ Op1( 0), CRn( 1), CRm( 0), Op2( 0), access_sctlr, NULL, c1_SCTLR },
{ Op1( 0), CRn( 2), CRm( 0), Op2( 0), access_vm_reg, NULL, c2_TTBR0 },
{ Op1( 0), CRn( 2), CRm( 0), Op2( 1), access_vm_reg, NULL, c2_TTBR1 },
@ -713,6 +739,7 @@ static const struct sys_reg_desc cp15_regs[] = {
static const struct sys_reg_desc cp15_64_regs[] = {
{ Op1( 0), CRn( 0), CRm( 2), Op2( 0), access_vm_reg, NULL, c2_TTBR0 },
{ Op1( 0), CRn( 0), CRm(12), Op2( 0), access_gic_sgi },
{ Op1( 1), CRn( 0), CRm( 2), Op2( 0), access_vm_reg, NULL, c2_TTBR1 },
};

1
include/kvm/arm_vgic.h
View File

@ -307,6 +307,7 @@ void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu);
void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu);
int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int irq_num,
bool level);
void vgic_v3_dispatch_sgi(struct kvm_vcpu *vcpu, u64 reg);
int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu);
bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run,
struct kvm_exit_mmio *mmio);

111
virt/kvm/arm/vgic-v3-emul.c
View File

@ -841,6 +841,117 @@ void vgic_v3_init_emulation(struct kvm *kvm)
kvm->arch.max_vcpus = KVM_MAX_VCPUS;
}
/*
* Compare a given affinity (level 1-3 and a level 0 mask, from the SGI
* generation register ICC_SGI1R_EL1) with a given VCPU.
* If the VCPU's MPIDR matches, return the level0 affinity, otherwise
* return -1.
*/
static int match_mpidr(u64 sgi_aff, u16 sgi_cpu_mask, struct kvm_vcpu *vcpu)
{
unsigned long affinity;
int level0;
/*
* Split the current VCPU's MPIDR into affinity level 0 and the
* rest as this is what we have to compare against.
*/
affinity = kvm_vcpu_get_mpidr_aff(vcpu);
level0 = MPIDR_AFFINITY_LEVEL(affinity, 0);
affinity &= ~MPIDR_LEVEL_MASK;
/* bail out if the upper three levels don't match */
if (sgi_aff != affinity)
return -1;
/* Is this VCPU's bit set in the mask ? */
if (!(sgi_cpu_mask & BIT(level0)))
return -1;
return level0;
}
#define SGI_AFFINITY_LEVEL(reg, level) \
((((reg) & ICC_SGI1R_AFFINITY_## level ##_MASK) \
>> ICC_SGI1R_AFFINITY_## level ##_SHIFT) << MPIDR_LEVEL_SHIFT(level))
/**
* vgic_v3_dispatch_sgi - handle SGI requests from VCPUs
* @vcpu: The VCPU requesting a SGI
* @reg: The value written into the ICC_SGI1R_EL1 register by that VCPU
*
* With GICv3 (and ARE=1) CPUs trigger SGIs by writing to a system register.
* This will trap in sys_regs.c and call this function.
* This ICC_SGI1R_EL1 register contains the upper three affinity levels of the
* target processors as well as a bitmask of 16 Aff0 CPUs.
* If the interrupt routing mode bit is not set, we iterate over all VCPUs to
* check for matching ones. If this bit is set, we signal all, but not the
* calling VCPU.
*/
void vgic_v3_dispatch_sgi(struct kvm_vcpu *vcpu, u64 reg)
{
struct kvm *kvm = vcpu->kvm;
struct kvm_vcpu *c_vcpu;
struct vgic_dist *dist = &kvm->arch.vgic;
u16 target_cpus;
u64 mpidr;
int sgi, c;
int vcpu_id = vcpu->vcpu_id;
bool broadcast;
int updated = 0;
sgi = (reg & ICC_SGI1R_SGI_ID_MASK) >> ICC_SGI1R_SGI_ID_SHIFT;
broadcast = reg & BIT(ICC_SGI1R_IRQ_ROUTING_MODE_BIT);
target_cpus = (reg & ICC_SGI1R_TARGET_LIST_MASK) >> ICC_SGI1R_TARGET_LIST_SHIFT;
mpidr = SGI_AFFINITY_LEVEL(reg, 3);
mpidr |= SGI_AFFINITY_LEVEL(reg, 2);
mpidr |= SGI_AFFINITY_LEVEL(reg, 1);
/*
* We take the dist lock here, because we come from the sysregs
* code path and not from the MMIO one (which already takes the lock).
*/
spin_lock(&dist->lock);
/*
* We iterate over all VCPUs to find the MPIDRs matching the request.
* If we have handled one CPU, we clear it's bit to detect early
* if we are already finished. This avoids iterating through all
* VCPUs when most of the times we just signal a single VCPU.
*/
kvm_for_each_vcpu(c, c_vcpu, kvm) {
/* Exit early if we have dealt with all requested CPUs */
if (!broadcast && target_cpus == 0)
break;
/* Don't signal the calling VCPU */
if (broadcast && c == vcpu_id)
continue;
if (!broadcast) {
int level0;
level0 = match_mpidr(mpidr, target_cpus, c_vcpu);
if (level0 == -1)
continue;
/* remove this matching VCPU from the mask */
target_cpus &= ~BIT(level0);
}
/* Flag the SGI as pending */
vgic_dist_irq_set_pending(c_vcpu, sgi);
updated = 1;
kvm_debug("SGI%d from CPU%d to CPU%d\n", sgi, vcpu_id, c);
}
if (updated)
vgic_update_state(vcpu->kvm);
spin_unlock(&dist->lock);
if (updated)
vgic_kick_vcpus(vcpu->kvm);
}
static int vgic_v3_create(struct kvm_device *dev, u32 type)
{
return kvm_vgic_create(dev->kvm, type);