Skip to content

Commit

Permalink
KVM: ARM: VFP userspace interface
Browse files Browse the repository at this point in the history 
We use space #18 for floating point regs.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
  • Loading branch information
Rusty Russell authored and Christoffer Dall committed Jan 23, 2013
1 parent c27581e commit 4fe21e4
Show file tree
Hide file tree
Showing 3 changed files with 196 additions and 0 deletions.
6 changes: 6 additions & 0 deletions Documentation/virtual/kvm/api.txt
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1808,6 +1808,12 @@ ARM 64-bit CP15 registers have the following id bit patterns:
ARM CCSIDR registers are demultiplexed by CSSELR value:
0x4002 0000 0011 00 <csselr:8>

ARM 32-bit VFP control registers have the following id bit patterns:
0x4002 0000 0012 1 <regno:12>

ARM 64-bit FP registers have the following id bit patterns:
0x4002 0000 0012 0 <regno:12>

4.69 KVM_GET_ONE_REG

Capability: KVM_CAP_ONE_REG
Expand Down
12 changes: 12 additions & 0 deletions arch/arm/include/uapi/asm/kvm.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -112,6 +112,18 @@ struct kvm_arch_memory_slot {
#define KVM_REG_ARM_DEMUX_VAL_MASK 0x00000000000000FF
#define KVM_REG_ARM_DEMUX_VAL_SHIFT 0

/* VFP registers: we could overload CP10 like ARM does, but that's ugly. */
#define KVM_REG_ARM_VFP (0x0012 << KVM_REG_ARM_COPROC_SHIFT)
#define KVM_REG_ARM_VFP_MASK 0x000000000000FFFF
#define KVM_REG_ARM_VFP_BASE_REG 0x0
#define KVM_REG_ARM_VFP_FPSID 0x1000
#define KVM_REG_ARM_VFP_FPSCR 0x1001
#define KVM_REG_ARM_VFP_MVFR1 0x1006
#define KVM_REG_ARM_VFP_MVFR0 0x1007
#define KVM_REG_ARM_VFP_FPEXC 0x1008
#define KVM_REG_ARM_VFP_FPINST 0x1009
#define KVM_REG_ARM_VFP_FPINST2 0x100A


/* KVM_IRQ_LINE irq field index values */
#define KVM_ARM_IRQ_TYPE_SHIFT 24
Expand Down
178 changes: 178 additions & 0 deletions arch/arm/kvm/coproc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,8 @@
#include <asm/cacheflush.h>
#include <asm/cputype.h>
#include <trace/events/kvm.h>
#include <asm/vfp.h>
#include "../vfp/vfpinstr.h"

#include "trace.h"
#include "coproc.h"
Expand Down Expand Up @@ -653,6 +655,170 @@ static int demux_c15_set(u64 id, void __user *uaddr)
}
}

#ifdef CONFIG_VFPv3
static const int vfp_sysregs[] = { KVM_REG_ARM_VFP_FPEXC,
KVM_REG_ARM_VFP_FPSCR,
KVM_REG_ARM_VFP_FPINST,
KVM_REG_ARM_VFP_FPINST2,
KVM_REG_ARM_VFP_MVFR0,
KVM_REG_ARM_VFP_MVFR1,
KVM_REG_ARM_VFP_FPSID };

static unsigned int num_fp_regs(void)
{
if (((fmrx(MVFR0) & MVFR0_A_SIMD_MASK) >> MVFR0_A_SIMD_BIT) == 2)
return 32;
else
return 16;
}

static unsigned int num_vfp_regs(void)
{
/* Normal FP regs + control regs. */
return num_fp_regs() + ARRAY_SIZE(vfp_sysregs);
}

static int copy_vfp_regids(u64 __user *uindices)
{
unsigned int i;
const u64 u32reg = KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_VFP;
const u64 u64reg = KVM_REG_ARM | KVM_REG_SIZE_U64 | KVM_REG_ARM_VFP;

for (i = 0; i < num_fp_regs(); i++) {
if (put_user((u64reg | KVM_REG_ARM_VFP_BASE_REG) + i,
uindices))
return -EFAULT;
uindices++;
}

for (i = 0; i < ARRAY_SIZE(vfp_sysregs); i++) {
if (put_user(u32reg | vfp_sysregs[i], uindices))
return -EFAULT;
uindices++;
}

return num_vfp_regs();
}

static int vfp_get_reg(const struct kvm_vcpu *vcpu, u64 id, void __user *uaddr)
{
u32 vfpid = (id & KVM_REG_ARM_VFP_MASK);
u32 val;

/* Fail if we have unknown bits set. */
if (id & ~(KVM_REG_ARCH_MASK|KVM_REG_SIZE_MASK|KVM_REG_ARM_COPROC_MASK
| ((1 << KVM_REG_ARM_COPROC_SHIFT)-1)))
return -ENOENT;

if (vfpid < num_fp_regs()) {
if (KVM_REG_SIZE(id) != 8)
return -ENOENT;
return reg_to_user(uaddr, &vcpu->arch.vfp_guest.fpregs[vfpid],
id);
}

/* FP control registers are all 32 bit. */
if (KVM_REG_SIZE(id) != 4)
return -ENOENT;

switch (vfpid) {
case KVM_REG_ARM_VFP_FPEXC:
return reg_to_user(uaddr, &vcpu->arch.vfp_guest.fpexc, id);
case KVM_REG_ARM_VFP_FPSCR:
return reg_to_user(uaddr, &vcpu->arch.vfp_guest.fpscr, id);
case KVM_REG_ARM_VFP_FPINST:
return reg_to_user(uaddr, &vcpu->arch.vfp_guest.fpinst, id);
case KVM_REG_ARM_VFP_FPINST2:
return reg_to_user(uaddr, &vcpu->arch.vfp_guest.fpinst2, id);
case KVM_REG_ARM_VFP_MVFR0:
val = fmrx(MVFR0);
return reg_to_user(uaddr, &val, id);
case KVM_REG_ARM_VFP_MVFR1:
val = fmrx(MVFR1);
return reg_to_user(uaddr, &val, id);
case KVM_REG_ARM_VFP_FPSID:
val = fmrx(FPSID);
return reg_to_user(uaddr, &val, id);
default:
return -ENOENT;
}
}

static int vfp_set_reg(struct kvm_vcpu *vcpu, u64 id, const void __user *uaddr)
{
u32 vfpid = (id & KVM_REG_ARM_VFP_MASK);
u32 val;

/* Fail if we have unknown bits set. */
if (id & ~(KVM_REG_ARCH_MASK|KVM_REG_SIZE_MASK|KVM_REG_ARM_COPROC_MASK
| ((1 << KVM_REG_ARM_COPROC_SHIFT)-1)))
return -ENOENT;

if (vfpid < num_fp_regs()) {
if (KVM_REG_SIZE(id) != 8)
return -ENOENT;
return reg_from_user(&vcpu->arch.vfp_guest.fpregs[vfpid],
uaddr, id);
}

/* FP control registers are all 32 bit. */
if (KVM_REG_SIZE(id) != 4)
return -ENOENT;

switch (vfpid) {
case KVM_REG_ARM_VFP_FPEXC:
return reg_from_user(&vcpu->arch.vfp_guest.fpexc, uaddr, id);
case KVM_REG_ARM_VFP_FPSCR:
return reg_from_user(&vcpu->arch.vfp_guest.fpscr, uaddr, id);
case KVM_REG_ARM_VFP_FPINST:
return reg_from_user(&vcpu->arch.vfp_guest.fpinst, uaddr, id);
case KVM_REG_ARM_VFP_FPINST2:
return reg_from_user(&vcpu->arch.vfp_guest.fpinst2, uaddr, id);
/* These are invariant. */
case KVM_REG_ARM_VFP_MVFR0:
if (reg_from_user(&val, uaddr, id))
return -EFAULT;
if (val != fmrx(MVFR0))
return -EINVAL;
return 0;
case KVM_REG_ARM_VFP_MVFR1:
if (reg_from_user(&val, uaddr, id))
return -EFAULT;
if (val != fmrx(MVFR1))
return -EINVAL;
return 0;
case KVM_REG_ARM_VFP_FPSID:
if (reg_from_user(&val, uaddr, id))
return -EFAULT;
if (val != fmrx(FPSID))
return -EINVAL;
return 0;
default:
return -ENOENT;
}
}
#else /* !CONFIG_VFPv3 */
static unsigned int num_vfp_regs(void)
{
return 0;
}

static int copy_vfp_regids(u64 __user *uindices)
{
return 0;
}

static int vfp_get_reg(const struct kvm_vcpu *vcpu, u64 id, void __user *uaddr)
{
return -ENOENT;
}

static int vfp_set_reg(struct kvm_vcpu *vcpu, u64 id, const void __user *uaddr)
{
return -ENOENT;
}
#endif /* !CONFIG_VFPv3 */

int kvm_arm_coproc_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
const struct coproc_reg *r;
Expand All @@ -661,6 +827,9 @@ int kvm_arm_coproc_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
return demux_c15_get(reg->id, uaddr);

if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_VFP)
return vfp_get_reg(vcpu, reg->id, uaddr);

r = index_to_coproc_reg(vcpu, reg->id);
if (!r)
return get_invariant_cp15(reg->id, uaddr);
Expand All @@ -677,6 +846,9 @@ int kvm_arm_coproc_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
return demux_c15_set(reg->id, uaddr);

if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_VFP)
return vfp_set_reg(vcpu, reg->id, uaddr);

r = index_to_coproc_reg(vcpu, reg->id);
if (!r)
return set_invariant_cp15(reg->id, uaddr);
Expand Down Expand Up @@ -788,6 +960,7 @@ unsigned long kvm_arm_num_coproc_regs(struct kvm_vcpu *vcpu)
{
return ARRAY_SIZE(invariant_cp15)
+ num_demux_regs()
+ num_vfp_regs()
+ walk_cp15(vcpu, (u64 __user *)NULL);
}

Expand All @@ -808,6 +981,11 @@ int kvm_arm_copy_coproc_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
return err;
uindices += err;

err = copy_vfp_regids(uindices);
if (err < 0)
return err;
uindices += err;

return write_demux_regids(uindices);
}

Expand Down

0 comments on commit 4fe21e4

Please sign in to comment.