diff mbox series

[v3,13/27] KVM: arm64: Restructure FGT register switching

Message ID 20230808114711.2013842-14-maz@kernel.org (mailing list archive)
State New, archived
Headers show
Series KVM: arm64: NV trap forwarding infrastructure | expand

Commit Message

Marc Zyngier Aug. 8, 2023, 11:46 a.m. UTC
As we're about to majorly extend the handling of FGT registers,
restructure the code to actually save/restore the registers
as required. This is made easy thanks to the previous addition
of the EL2 registers, allowing us to use the host context for
this purpose.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: Miguel Luis <miguel.luis@oracle.com>
---
 arch/arm64/include/asm/kvm_arm.h        | 21 ++++++++++
 arch/arm64/kvm/hyp/include/hyp/switch.h | 56 +++++++++++++------------
 2 files changed, 50 insertions(+), 27 deletions(-)

Comments

Jing Zhang Aug. 11, 2023, 5:40 p.m. UTC | #1
Hi Marc,

On Tue, Aug 8, 2023 at 4:48 AM Marc Zyngier <maz@kernel.org> wrote:
>
> As we're about to majorly extend the handling of FGT registers,
> restructure the code to actually save/restore the registers
> as required. This is made easy thanks to the previous addition
> of the EL2 registers, allowing us to use the host context for
> this purpose.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> Reviewed-by: Eric Auger <eric.auger@redhat.com>
> Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
> Reviewed-by: Miguel Luis <miguel.luis@oracle.com>
> ---
>  arch/arm64/include/asm/kvm_arm.h        | 21 ++++++++++
>  arch/arm64/kvm/hyp/include/hyp/switch.h | 56 +++++++++++++------------
>  2 files changed, 50 insertions(+), 27 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
> index 028049b147df..85908aa18908 100644
> --- a/arch/arm64/include/asm/kvm_arm.h
> +++ b/arch/arm64/include/asm/kvm_arm.h
> @@ -333,6 +333,27 @@
>                                  BIT(18) |              \
>                                  GENMASK(16, 15))
>
> +/*
> + * FGT register definitions
> + *
> + * RES0 and polarity masks as of DDI0487J.a, to be updated as needed.
> + * We're not using the generated masks as they are usually ahead of
> + * the published ARM ARM, which we use as a reference.
> + *
> + * Once we get to a point where the two describe the same thing, we'll
> + * merge the definitions. One day.
> + */
> +#define __HFGRTR_EL2_RES0      (GENMASK(63, 56) | GENMASK(53, 51))
> +#define __HFGRTR_EL2_MASK      GENMASK(49, 0)
> +#define __HFGRTR_EL2_nMASK     (GENMASK(55, 54) | BIT(50))
> +
> +#define __HFGWTR_EL2_RES0      (GENMASK(63, 56) | GENMASK(53, 51) |    \
> +                                BIT(46) | BIT(42) | BIT(40) | BIT(28) | \
> +                                GENMASK(26, 25) | BIT(21) | BIT(18) |  \
> +                                GENMASK(15, 14) | GENMASK(10, 9) | BIT(2))
> +#define __HFGWTR_EL2_MASK      GENMASK(49, 0)
> +#define __HFGWTR_EL2_nMASK     (GENMASK(55, 54) | BIT(50))
> +
>  /* Hyp Prefetch Fault Address Register (HPFAR/HDFAR) */
>  #define HPFAR_MASK     (~UL(0xf))
>  /*
> diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
> index 4bddb8541bec..e096b16e85fd 100644
> --- a/arch/arm64/kvm/hyp/include/hyp/switch.h
> +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
> @@ -70,20 +70,19 @@ static inline void __activate_traps_fpsimd32(struct kvm_vcpu *vcpu)
>         }
>  }
>
> -static inline bool __hfgxtr_traps_required(void)
> -{
> -       if (cpus_have_final_cap(ARM64_SME))
> -               return true;
> -
> -       if (cpus_have_final_cap(ARM64_WORKAROUND_AMPERE_AC03_CPU_38))
> -               return true;
>
> -       return false;
> -}
>
> -static inline void __activate_traps_hfgxtr(void)
> +static inline void __activate_traps_hfgxtr(struct kvm_vcpu *vcpu)
>  {
> +       struct kvm_cpu_context *hctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
>         u64 r_clr = 0, w_clr = 0, r_set = 0, w_set = 0, tmp;
> +       u64 r_val, w_val;
> +
> +       if (!cpus_have_final_cap(ARM64_HAS_FGT))
> +               return;
> +
> +       ctxt_sys_reg(hctxt, HFGRTR_EL2) = read_sysreg_s(SYS_HFGRTR_EL2);
> +       ctxt_sys_reg(hctxt, HFGWTR_EL2) = read_sysreg_s(SYS_HFGWTR_EL2);
>
>         if (cpus_have_final_cap(ARM64_SME)) {
>                 tmp = HFGxTR_EL2_nSMPRI_EL1_MASK | HFGxTR_EL2_nTPIDR2_EL0_MASK;
> @@ -98,26 +97,31 @@ static inline void __activate_traps_hfgxtr(void)
>         if (cpus_have_final_cap(ARM64_WORKAROUND_AMPERE_AC03_CPU_38))
>                 w_set |= HFGxTR_EL2_TCR_EL1_MASK;
>
> -       sysreg_clear_set_s(SYS_HFGRTR_EL2, r_clr, r_set);
> -       sysreg_clear_set_s(SYS_HFGWTR_EL2, w_clr, w_set);
> +
> +       /* The default is not to trap anything but ACCDATA_EL1 */
> +       r_val = __HFGRTR_EL2_nMASK & ~HFGxTR_EL2_nACCDATA_EL1;
> +       r_val |= r_set;
> +       r_val &= ~r_clr;
> +
> +       w_val = __HFGWTR_EL2_nMASK & ~HFGxTR_EL2_nACCDATA_EL1;
> +       w_val |= w_set;
> +       w_val &= ~w_clr;
> +
> +       write_sysreg_s(r_val, SYS_HFGRTR_EL2);
> +       write_sysreg_s(w_val, SYS_HFGWTR_EL2);
>  }
>
> -static inline void __deactivate_traps_hfgxtr(void)
> +static inline void __deactivate_traps_hfgxtr(struct kvm_vcpu *vcpu)
>  {
> -       u64 r_clr = 0, w_clr = 0, r_set = 0, w_set = 0, tmp;
> +       struct kvm_cpu_context *hctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
>
> -       if (cpus_have_final_cap(ARM64_SME)) {
> -               tmp = HFGxTR_EL2_nSMPRI_EL1_MASK | HFGxTR_EL2_nTPIDR2_EL0_MASK;
> +       if (!cpus_have_final_cap(ARM64_HAS_FGT))
> +               return;
>
> -               r_set |= tmp;
> -               w_set |= tmp;
> -       }
> +       write_sysreg_s(ctxt_sys_reg(hctxt, HFGRTR_EL2), SYS_HFGRTR_EL2);
> +       write_sysreg_s(ctxt_sys_reg(hctxt, HFGWTR_EL2), SYS_HFGWTR_EL2);
>
> -       if (cpus_have_final_cap(ARM64_WORKAROUND_AMPERE_AC03_CPU_38))
> -               w_clr |= HFGxTR_EL2_TCR_EL1_MASK;
>
> -       sysreg_clear_set_s(SYS_HFGRTR_EL2, r_clr, r_set);
> -       sysreg_clear_set_s(SYS_HFGWTR_EL2, w_clr, w_set);
>  }
>
>  static inline void __activate_traps_common(struct kvm_vcpu *vcpu)
> @@ -145,8 +149,7 @@ static inline void __activate_traps_common(struct kvm_vcpu *vcpu)
>         vcpu->arch.mdcr_el2_host = read_sysreg(mdcr_el2);
>         write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
>
> -       if (__hfgxtr_traps_required())
> -               __activate_traps_hfgxtr();
> +       __activate_traps_hfgxtr(vcpu);
>  }
>
>  static inline void __deactivate_traps_common(struct kvm_vcpu *vcpu)
> @@ -162,8 +165,7 @@ static inline void __deactivate_traps_common(struct kvm_vcpu *vcpu)
>                 vcpu_clear_flag(vcpu, PMUSERENR_ON_CPU);
>         }
>
> -       if (__hfgxtr_traps_required())
> -               __deactivate_traps_hfgxtr();
> +       __deactivate_traps_hfgxtr(vcpu);
>  }
>
>  static inline void ___activate_traps(struct kvm_vcpu *vcpu)
> --
> 2.34.1
>
>

Reviewed-by: Jing Zhang <jingzhangos@google.com>

Jing
diff mbox series

Patch

diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index 028049b147df..85908aa18908 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -333,6 +333,27 @@ 
 				 BIT(18) |		\
 				 GENMASK(16, 15))
 
+/*
+ * FGT register definitions
+ *
+ * RES0 and polarity masks as of DDI0487J.a, to be updated as needed.
+ * We're not using the generated masks as they are usually ahead of
+ * the published ARM ARM, which we use as a reference.
+ *
+ * Once we get to a point where the two describe the same thing, we'll
+ * merge the definitions. One day.
+ */
+#define __HFGRTR_EL2_RES0	(GENMASK(63, 56) | GENMASK(53, 51))
+#define __HFGRTR_EL2_MASK	GENMASK(49, 0)
+#define __HFGRTR_EL2_nMASK	(GENMASK(55, 54) | BIT(50))
+
+#define __HFGWTR_EL2_RES0	(GENMASK(63, 56) | GENMASK(53, 51) |	\
+				 BIT(46) | BIT(42) | BIT(40) | BIT(28) | \
+				 GENMASK(26, 25) | BIT(21) | BIT(18) |	\
+				 GENMASK(15, 14) | GENMASK(10, 9) | BIT(2))
+#define __HFGWTR_EL2_MASK	GENMASK(49, 0)
+#define __HFGWTR_EL2_nMASK	(GENMASK(55, 54) | BIT(50))
+
 /* Hyp Prefetch Fault Address Register (HPFAR/HDFAR) */
 #define HPFAR_MASK	(~UL(0xf))
 /*
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index 4bddb8541bec..e096b16e85fd 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -70,20 +70,19 @@  static inline void __activate_traps_fpsimd32(struct kvm_vcpu *vcpu)
 	}
 }
 
-static inline bool __hfgxtr_traps_required(void)
-{
-	if (cpus_have_final_cap(ARM64_SME))
-		return true;
-
-	if (cpus_have_final_cap(ARM64_WORKAROUND_AMPERE_AC03_CPU_38))
-		return true;
 
-	return false;
-}
 
-static inline void __activate_traps_hfgxtr(void)
+static inline void __activate_traps_hfgxtr(struct kvm_vcpu *vcpu)
 {
+	struct kvm_cpu_context *hctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
 	u64 r_clr = 0, w_clr = 0, r_set = 0, w_set = 0, tmp;
+	u64 r_val, w_val;
+
+	if (!cpus_have_final_cap(ARM64_HAS_FGT))
+		return;
+
+	ctxt_sys_reg(hctxt, HFGRTR_EL2) = read_sysreg_s(SYS_HFGRTR_EL2);
+	ctxt_sys_reg(hctxt, HFGWTR_EL2) = read_sysreg_s(SYS_HFGWTR_EL2);
 
 	if (cpus_have_final_cap(ARM64_SME)) {
 		tmp = HFGxTR_EL2_nSMPRI_EL1_MASK | HFGxTR_EL2_nTPIDR2_EL0_MASK;
@@ -98,26 +97,31 @@  static inline void __activate_traps_hfgxtr(void)
 	if (cpus_have_final_cap(ARM64_WORKAROUND_AMPERE_AC03_CPU_38))
 		w_set |= HFGxTR_EL2_TCR_EL1_MASK;
 
-	sysreg_clear_set_s(SYS_HFGRTR_EL2, r_clr, r_set);
-	sysreg_clear_set_s(SYS_HFGWTR_EL2, w_clr, w_set);
+
+	/* The default is not to trap anything but ACCDATA_EL1 */
+	r_val = __HFGRTR_EL2_nMASK & ~HFGxTR_EL2_nACCDATA_EL1;
+	r_val |= r_set;
+	r_val &= ~r_clr;
+
+	w_val = __HFGWTR_EL2_nMASK & ~HFGxTR_EL2_nACCDATA_EL1;
+	w_val |= w_set;
+	w_val &= ~w_clr;
+
+	write_sysreg_s(r_val, SYS_HFGRTR_EL2);
+	write_sysreg_s(w_val, SYS_HFGWTR_EL2);
 }
 
-static inline void __deactivate_traps_hfgxtr(void)
+static inline void __deactivate_traps_hfgxtr(struct kvm_vcpu *vcpu)
 {
-	u64 r_clr = 0, w_clr = 0, r_set = 0, w_set = 0, tmp;
+	struct kvm_cpu_context *hctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
 
-	if (cpus_have_final_cap(ARM64_SME)) {
-		tmp = HFGxTR_EL2_nSMPRI_EL1_MASK | HFGxTR_EL2_nTPIDR2_EL0_MASK;
+	if (!cpus_have_final_cap(ARM64_HAS_FGT))
+		return;
 
-		r_set |= tmp;
-		w_set |= tmp;
-	}
+	write_sysreg_s(ctxt_sys_reg(hctxt, HFGRTR_EL2), SYS_HFGRTR_EL2);
+	write_sysreg_s(ctxt_sys_reg(hctxt, HFGWTR_EL2), SYS_HFGWTR_EL2);
 
-	if (cpus_have_final_cap(ARM64_WORKAROUND_AMPERE_AC03_CPU_38))
-		w_clr |= HFGxTR_EL2_TCR_EL1_MASK;
 
-	sysreg_clear_set_s(SYS_HFGRTR_EL2, r_clr, r_set);
-	sysreg_clear_set_s(SYS_HFGWTR_EL2, w_clr, w_set);
 }
 
 static inline void __activate_traps_common(struct kvm_vcpu *vcpu)
@@ -145,8 +149,7 @@  static inline void __activate_traps_common(struct kvm_vcpu *vcpu)
 	vcpu->arch.mdcr_el2_host = read_sysreg(mdcr_el2);
 	write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
 
-	if (__hfgxtr_traps_required())
-		__activate_traps_hfgxtr();
+	__activate_traps_hfgxtr(vcpu);
 }
 
 static inline void __deactivate_traps_common(struct kvm_vcpu *vcpu)
@@ -162,8 +165,7 @@  static inline void __deactivate_traps_common(struct kvm_vcpu *vcpu)
 		vcpu_clear_flag(vcpu, PMUSERENR_ON_CPU);
 	}
 
-	if (__hfgxtr_traps_required())
-		__deactivate_traps_hfgxtr();
+	__deactivate_traps_hfgxtr(vcpu);
 }
 
 static inline void ___activate_traps(struct kvm_vcpu *vcpu)