From: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx>
As we already store the floating point registers in the vector save area
in floating point register format when we don't have MACHINE_HAS_VX, we can
directly expose them to user space using a new sync flag.
The floating point registers will be valid when KVM_SYNC_FPRS is set. The
fpc will also be valid when KVM_SYNC_FPRS is set.
Either KVM_SYNC_FPRS or KVM_SYNC_VRS will be enabled, never both.
Let's also change two positions where we access vrs, making the code easier
to read and one comment superfluous.
Suggested-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Signed-off-by: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
arch/s390/include/uapi/asm/kvm.h | 8 ++++++--
arch/s390/kvm/kvm-s390.c | 12 +++++++-----
2 files changed, 13 insertions(+), 7 deletions(-)
diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h
index fe84bd5..347fe5a 100644
--- a/arch/s390/include/uapi/asm/kvm.h
+++ b/arch/s390/include/uapi/asm/kvm.h
@@ -154,6 +154,7 @@ struct kvm_guest_debug_arch {
#define KVM_SYNC_PFAULT (1UL << 5)
#define KVM_SYNC_VRS (1UL << 6)
#define KVM_SYNC_RICCB (1UL << 7)
+#define KVM_SYNC_FPRS (1UL << 8)
/* definition of registers in kvm_run */
struct kvm_sync_regs {
__u64 prefix; /* prefix register */
@@ -168,9 +169,12 @@ struct kvm_sync_regs {
__u64 pft; /* pfault token [PFAULT] */
__u64 pfs; /* pfault select [PFAULT] */
__u64 pfc; /* pfault compare [PFAULT] */
- __u64 vrs[32][2]; /* vector registers */
+ union {
+ __u64 vrs[32][2]; /* vector registers (KVM_SYNC_VRS) */
+ __u64 fprs[16]; /* fp registers (KVM_SYNC_FPRS) */
+ };
__u8 reserved[512]; /* for future vector expansion */
- __u32 fpc; /* only valid with vector registers */
+ __u32 fpc; /* valid on KVM_SYNC_VRS or KVM_SYNC_FPRS */
__u8 padding[52]; /* riccb needs to be 64byte aligned */
__u8 riccb[64]; /* runtime instrumentation controls block */
};
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 8fcdf98..2270fe4 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1419,6 +1419,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
*/
if (MACHINE_HAS_VX)
vcpu->run->kvm_valid_regs |= KVM_SYNC_VRS;
+ else
+ vcpu->run->kvm_valid_regs |= KVM_SYNC_FPRS;
if (kvm_is_ucontrol(vcpu->kvm))
return __kvm_ucontrol_vcpu_init(vcpu);
@@ -1433,10 +1435,10 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
vcpu->arch.host_fpregs.fpc = current->thread.fpu.fpc;
vcpu->arch.host_fpregs.regs = current->thread.fpu.regs;
- /* Depending on MACHINE_HAS_VX, data stored to vrs either
- * has vector register or floating point register format.
- */
- current->thread.fpu.regs = vcpu->run->s.regs.vrs;
+ if (MACHINE_HAS_VX)
+ current->thread.fpu.regs = vcpu->run->s.regs.vrs;
+ else
+ current->thread.fpu.regs = vcpu->run->s.regs.fprs;
current->thread.fpu.fpc = vcpu->run->s.regs.fpc;
if (test_fp_ctl(current->thread.fpu.fpc))
/* User space provided an invalid FPC, let's clear it */
@@ -2389,7 +2391,7 @@ int kvm_s390_store_status_unloaded(struct kvm_vcpu *vcpu, unsigned long gpa)
fprs, 128);
} else {
rc = write_guest_abs(vcpu, gpa + __LC_FPREGS_SAVE_AREA,
- vcpu->run->s.regs.vrs, 128);
+ vcpu->run->s.regs.fprs, 128);
}
rc |= write_guest_abs(vcpu, gpa + __LC_GPREGS_SAVE_AREA,
vcpu->run->s.regs.gprs, 128);
--
2.3.0
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