[PATCH v2 12/14] KVM: ARM: VFP userspace interface

Christoffer Dall
2012-10-01T09:11:27Z

From: Rusty Russell <rusty.russell@linaro.org>

We use space #18 for floating point regs.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
---
Documentation/virtual/kvm/api.txt | 6 +
arch/arm/include/asm/kvm.h | 12 ++
arch/arm/kvm/coproc.c | 178 +++++++++++++++++++++++++++++++++++++
3 files changed, 196 insertions(+)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 74223f3..7695425 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1765,6 +1765,12 @@ 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 <selector:3>
+
+ARM 64-bit FP registers have the following id bit patterns:
+ 0x4002 0000 0012 0 <selector:3>
+
4.69 KVM_GET_ONE_REG

Capability: KVM_CAP_ONE_REG
diff --git a/arch/arm/include/asm/kvm.h b/arch/arm/include/asm/kvm.h
index 0ab12fd..b6eaf0c 100644
--- a/arch/arm/include/asm/kvm.h
+++ b/arch/arm/include/asm/kvm.h
@@ -95,6 +95,18 @@ struct kvm_reg_list {
#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
diff --git a/arch/arm/kvm/coproc.c b/arch/arm/kvm/coproc.c
index 7addf62..b8bddd7 100644
--- a/arch/arm/kvm/coproc.c
+++ b/arch/arm/kvm/coproc.c
@@ -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"
@@ -652,6 +654,170 @@ 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;
@@ -660,6 +826,9 @@ 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);
@@ -676,6 +845,9 @@ 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);
@@ -787,6 +959,7 @@ 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);
}

@@ -807,6 +980,11 @@ 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);
}