Similar to armv7 add helper functions to enable access to fp/smid registers on
guest entry. Save guest fpexc32_el2 on vcpu_put, check if guest is 32 bit.
Save guest and restore host registers from host kernel, and check
if fp/simd registers are dirty, lastly add cptr_el2 vcpu field.
Signed-off-by: Mario Smarduch <m.smarduch@xxxxxxxxxxx>
---
arch/arm/include/asm/kvm_emulate.h | 12 ++++++++++++
arch/arm64/include/asm/kvm_asm.h | 5 +++++
arch/arm64/include/asm/kvm_emulate.h | 26 ++++++++++++++++++++++++--
arch/arm64/include/asm/kvm_host.h | 12 +++++++++++-
arch/arm64/kvm/hyp/hyp-entry.S | 26 ++++++++++++++++++++++++++
5 files changed, 78 insertions(+), 3 deletions(-)
diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h
index d4d9da1..a434dc5 100644
--- a/arch/arm/include/asm/kvm_emulate.h
+++ b/arch/arm/include/asm/kvm_emulate.h
@@ -284,6 +284,12 @@ static inline bool vcpu_vfp_isdirty(struct kvm_vcpu *vcpu)
{
return !(vcpu->arch.hcptr & (HCPTR_TCP(10) | HCPTR_TCP(11)));
}
+
+static inline bool vcpu_guest_is_32bit(struct kvm_vcpu *vcpu)
+{
+ return true;
+}
+static inline void vcpu_save_fpexc(struct kvm_vcpu *vcpu) {}
#else
static inline void vcpu_trap_vfp_enable(struct kvm_vcpu *vcpu)
{
@@ -295,6 +301,12 @@ static inline bool vcpu_vfp_isdirty(struct kvm_vcpu *vcpu)
{
return false;
}
+
+static inline bool vcpu_guest_is_32bit(struct kvm_vcpu *vcpu)
+{
+ return true;
+}
+static inline void vcpu_save_fpexc(struct kvm_vcpu *vcpu) {}
#endif
#endif /* __ARM_KVM_EMULATE_H__ */
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 52b777b..ddae814 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -48,6 +48,11 @@ extern u64 __vgic_v3_get_ich_vtr_el2(void);
extern u32 __kvm_get_mdcr_el2(void);
+extern void __fpsimd_prepare_fpexc32(void);
+extern void __fpsimd_save_fpexc32(struct kvm_vcpu *vcpu);
+extern void __fpsimd_save_state(struct user_fpsimd_state *);
+extern void __fpsimd_restore_state(struct user_fpsimd_state *);
+
#endif
#endif /* __ARM_KVM_ASM_H__ */
diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index ffe8ccf..f8203c7 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -299,12 +299,34 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu,
return data; /* Leave LE untouched */
}
-static inline void vcpu_trap_vfp_enable(struct kvm_vcpu *vcpu) {}
+static inline bool vcpu_guest_is_32bit(struct kvm_vcpu *vcpu)
+{
+ return !(vcpu->arch.hcr_el2 & HCR_RW);
+}
+
+static inline void vcpu_trap_vfp_enable(struct kvm_vcpu *vcpu)
+{
+ /* For 32 bit guest enable access to fp/simd registers */
+ if (vcpu_guest_is_32bit(vcpu))
+ vcpu_prepare_fpexc();
+
+ vcpu->arch.cptr_el2 = CPTR_EL2_TTA | CPTR_EL2_TFP;
+}
+
static inline void vcpu_restore_host_fpexc(struct kvm_vcpu *vcpu) {}
static inline bool vcpu_vfp_isdirty(struct kvm_vcpu *vcpu)
{
- return false;
+ return !(vcpu->arch.cptr_el2 & CPTR_EL2_TFP);
+}
+
+static inline void vcpu_restore_host_vfp_state(struct kvm_vcpu *vcpu)
+{
+ struct kvm_cpu_context *host_ctxt = vcpu->arch.host_cpu_context;
+ struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt;
+
+ __fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs);
+ __fpsimd_restore_state(&host_ctxt->gp_regs.fp_regs);
}
#endif /* __ARM64_KVM_EMULATE_H__ */
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index bfe4d4e..5d0c256 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -26,6 +26,7 @@
#include <linux/kvm_types.h>
#include <asm/kvm.h>
#include <asm/kvm_mmio.h>
+#include <asm/kvm_asm.h>
#define __KVM_HAVE_ARCH_INTC_INITIALIZED
@@ -180,6 +181,7 @@ struct kvm_vcpu_arch {
/* HYP configuration */
u64 hcr_el2;
u32 mdcr_el2;
+ u32 cptr_el2;
/* Exception Information */
struct kvm_vcpu_fault_info fault;
@@ -338,7 +340,15 @@ static inline void kvm_arch_sync_events(struct kvm *kvm) {}
static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
-static inline void vcpu_restore_host_vfp_state(struct kvm_vcpu *vcpu) {}
+static inline void vcpu_prepare_fpexc(void)
+{
+ kvm_call_hyp(__fpsimd_prepare_fpexc32);
+}
+
+static inline void vcpu_save_fpexc(struct kvm_vcpu *vcpu)
+{
+ kvm_call_hyp(__fpsimd_save_fpexc32, vcpu);
+}
void kvm_arm_init_debug(void);
void kvm_arm_setup_debug(struct kvm_vcpu *vcpu);
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 93e8d983..a9235e2 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -164,6 +164,32 @@ ENTRY(__hyp_do_panic)
eret
ENDPROC(__hyp_do_panic)
+/**
+ * void __fpsimd_prepare_fpexc32(void) -
+ * We may be entering the guest and set CPTR_EL2.TFP to trap all floating
+ * point register accesses to EL2, however, the ARM manual clearly states
+ * that traps are only taken to EL2 if the operation would not otherwise
+ * trap to EL1. Therefore, always make sure that for 32-bit guests,
+ * we set FPEXC.EN to prevent traps to EL1, when setting the TFP bit.
+ */
+ENTRY(__fpsimd_prepare_fpexc32)
+ mov x2, #(1 << 30)
+ msr fpexc32_el2, x2
+ ret
+ENDPROC(__fpsimd_prepare_fpexc32)
+
+/**
+ * void __fpsimd_save_fpexc32(void) -
+ * This function restores guest FPEXC to its vcpu context, we call this
+ * function from vcpu_put.
+ */
+ENTRY(__fpsimd_save_fpexc32)
+ kern_hyp_va x0
+ mrs x2, fpexc32_el2
+ str x2, [x0, #VCPU_FPEXC32_EL2]
+ ret
+ENDPROC(__fpsimd_save_fpexc32)
+
.macro invalid_vector label, target = __hyp_panic
.align 2
\label:
--
1.9.1
--
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