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From: Mark Rutland <mark.rutland@arm.com>
To: Marc Zyngier <maz@kernel.org>
Cc: Andre Przywara <andre.przywara@arm.com>,
	Dave Martin <Dave.Martin@arm.com>,
	kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org
Subject: Re: [PATCH v2 12/94] KVM: arm64: nv: Add EL2->EL1 translation helpers
Date: Mon, 17 Feb 2020 14:56:31 +0000
Message-ID: <20200217145630.GD47755@lakrids.cambridge.arm.com> (raw)
In-Reply-To: <20200211174938.27809-13-maz@kernel.org>

On Tue, Feb 11, 2020 at 05:48:16PM +0000, Marc Zyngier wrote:
> Some EL2 system registers immediately affect the current execution
> of the system, so we need to use their respective EL1 counterparts.
> For this we need to define a mapping between the two.
> 
> These helpers will get used in subsequent patches.
> 
> Co-developed-by: Andre Przywara <andre.przywara@arm.com>
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  arch/arm64/include/asm/kvm_emulate.h |  6 ++++
>  arch/arm64/kvm/sys_regs.c            | 48 ++++++++++++++++++++++++++++
>  2 files changed, 54 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
> index 282e9ddbe1bc..486978d0346b 100644
> --- a/arch/arm64/include/asm/kvm_emulate.h
> +++ b/arch/arm64/include/asm/kvm_emulate.h
> @@ -58,6 +58,12 @@ void kvm_emulate_nested_eret(struct kvm_vcpu *vcpu);
>  int kvm_inject_nested_sync(struct kvm_vcpu *vcpu, u64 esr_el2);
>  int kvm_inject_nested_irq(struct kvm_vcpu *vcpu);
>  
> +u64 translate_tcr(u64 tcr);
> +u64 translate_cptr(u64 tcr);
> +u64 translate_sctlr(u64 tcr);
> +u64 translate_ttbr0(u64 tcr);
> +u64 translate_cnthctl(u64 tcr);

Sorry to bikeshed, but could we please make the direction of translation
explicit in the name? e.g. tcr_el2_to_tcr_el1(), or tcr_el2_to_el1()?

> +
>  static inline bool vcpu_el1_is_32bit(struct kvm_vcpu *vcpu)
>  {
>  	return !(vcpu->arch.hcr_el2 & HCR_RW);
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 4b5310ea3bf8..634d3ee6799c 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -65,6 +65,54 @@ static bool write_to_read_only(struct kvm_vcpu *vcpu,
>  	return false;
>  }
>  
> +static u64 tcr_el2_ips_to_tcr_el1_ps(u64 tcr_el2)
> +{
> +	return ((tcr_el2 & TCR_EL2_PS_MASK) >> TCR_EL2_PS_SHIFT)
> +		<< TCR_IPS_SHIFT;
> +}
> +
> +u64 translate_tcr(u64 tcr)
> +{
> +	return TCR_EPD1_MASK |				/* disable TTBR1_EL1 */
> +	       ((tcr & TCR_EL2_TBI) ? TCR_TBI0 : 0) |
> +	       tcr_el2_ips_to_tcr_el1_ps(tcr) |
> +	       (tcr & TCR_EL2_TG0_MASK) |
> +	       (tcr & TCR_EL2_ORGN0_MASK) |
> +	       (tcr & TCR_EL2_IRGN0_MASK) |
> +	       (tcr & TCR_EL2_T0SZ_MASK);
> +}

I'm guessing this is only meant to cover a !VHE guest EL2 for the
moment, so only covers HCR_EL2.E2H=0? It might be worth mentioning in
the commit message.

It looks like this is missing some bits (e.g. TBID, HPD, HD, HA) that
could apply to the Guest-EL2 Stage-1. Maybe those are added by later
patches, but that's not obvious to me at this point in the series.

> +
> +u64 translate_cptr(u64 cptr_el2)
> +{
> +	u64 cpacr_el1 = 0;
> +
> +	if (!(cptr_el2 & CPTR_EL2_TFP))
> +		cpacr_el1 |= CPACR_EL1_FPEN;
> +	if (cptr_el2 & CPTR_EL2_TTA)
> +		cpacr_el1 |= CPACR_EL1_TTA;
> +	if (!(cptr_el2 & CPTR_EL2_TZ))
> +		cpacr_el1 |= CPACR_EL1_ZEN;
> +
> +	return cpacr_el1;
> +}

Looking in ARM DDI 0487E.a I also see TCPAC and TAM; I guess we don't
need to map those to anthing?

> +
> +u64 translate_sctlr(u64 sctlr)
> +{
> +	/* Bit 20 is RES1 in SCTLR_EL1, but RES0 in SCTLR_EL2 */
> +	return sctlr | BIT(20);
> +}

Looking in ARM DDI 0487E.a section D13.2.105, bit 20 is TSCXT, so this
might need to be reconsidered.

> +
> +u64 translate_ttbr0(u64 ttbr0)
> +{
> +	/* Force ASID to 0 (ASID 0 or RES0) */
> +	return ttbr0 & ~GENMASK_ULL(63, 48);
> +}

Again, I assume this is only meant to provide a !VHE EL2 as this stands.

> +
> +u64 translate_cnthctl(u64 cnthctl)
> +{
> +	return ((cnthctl & 0x3) << 10) | (cnthctl & 0xfc);
> +}

I assume this yields CNTKCTL_EL1, but I don't entirely follow. For
virtual-EL2 don't we have to force EL1P(C)TEN so that virtual-EL2
accesses don't trap?

Thanks,
Mark.
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  reply index

Thread overview: 104+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-11 17:48 [PATCH v2 00/94] KVM: arm64: ARMv8.3/8.4 Nested Virtualization support Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 01/94] KVM: arm64: Move __load_guest_stage2 to kvm_mmu.h Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 02/94] arm64: Add ARM64_HAS_NESTED_VIRT cpufeature Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 03/94] KVM: arm64: nv: Introduce nested virtualization VCPU feature Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 04/94] KVM: arm64: nv: Reset VCPU to EL2 registers if VCPU nested virt is set Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 05/94] KVM: arm64: nv: Allow userspace to set PSR_MODE_EL2x Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 06/94] KVM: arm64: nv: Add EL2 system registers to vcpu context Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 07/94] KVM: arm64: nv: Reset VMPIDR_EL2 and VPIDR_EL2 to sane values Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 08/94] KVM: arm64: nv: Add nested virt VCPU primitives for vEL2 VCPU state Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 09/94] KVM: arm64: nv: Support virtual EL2 exceptions Marc Zyngier
2020-02-17 12:52   ` Mark Rutland
2020-02-17 13:41     ` Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 10/94] KVM: arm64: nv: Inject HVC exceptions to the virtual EL2 Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 11/94] KVM: arm64: nv: Handle trapped ERET from " Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 12/94] KVM: arm64: nv: Add EL2->EL1 translation helpers Marc Zyngier
2020-02-17 14:56   ` Mark Rutland [this message]
2020-02-17 17:43     ` Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 13/94] KVM: arm64: nv: Refactor vcpu_{read,write}_sys_reg Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 14/94] KVM: arm64: nv: Handle virtual EL2 registers in vcpu_read/write_sys_reg() Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 15/94] KVM: arm64: nv: Handle SPSR_EL2 specially Marc Zyngier
2020-02-17 15:04   ` Mark Rutland
2020-02-11 17:48 ` [PATCH v2 16/94] KVM: arm64: nv: Handle HCR_EL2.E2H specially Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 17/94] KVM: arm64: nv: Save/Restore vEL2 sysregs Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 18/94] KVM: arm64: nv: Emulate PSTATE.M for a guest hypervisor Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 19/94] KVM: arm64: nv: Trap EL1 VM register accesses in virtual EL2 Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 20/94] KVM: arm64: nv: Trap SPSR_EL1, ELR_EL1 and VBAR_EL1 from " Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 21/94] KVM: arm64: nv: Trap CPACR_EL1 access in " Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 22/94] KVM: arm64: nv: Handle PSCI call via smc from the guest Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 23/94] KVM: arm64: nv: Respect virtual HCR_EL2.TWX setting Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 24/94] KVM: arm64: nv: Respect virtual CPTR_EL2.{TFP, FPEN} settings Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 25/94] KVM: arm64: nv: Respect the virtual HCR_EL2.NV bit setting Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 26/94] KVM: arm64: nv: Respect virtual HCR_EL2.TVM and TRVM settings Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 27/94] KVM: arm64: nv: Respect the virtual HCR_EL2.NV1 bit setting Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 28/94] KVM: arm64: nv: Emulate EL12 register accesses from the virtual EL2 Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 29/94] KVM: arm64: nv: Forward debug traps to the nested guest Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 30/94] KVM: arm64: nv: Configure HCR_EL2 for nested virtualization Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 31/94] KVM: arm64: nv: Only toggle cache for virtual EL2 when SCTLR_EL2 changes Marc Zyngier
2020-02-17 15:13   ` Mark Rutland
2020-02-11 17:48 ` [PATCH v2 32/94] KVM: arm64: nv: Filter out unsupported features from ID regs Marc Zyngier
2020-02-17 15:17   ` Mark Rutland
2020-02-11 17:48 ` [PATCH v2 33/94] KVM: arm64: nv: Hide RAS from nested guests Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 34/94] KVM: arm64: nv: Use ARMv8.5-GTG to advertise supported Stage-2 page sizes Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 35/94] KVM: arm64: Check advertised Stage-2 page size capability Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 36/94] KVM: arm/arm64: nv: Factor out stage 2 page table data from struct kvm Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 37/94] KVM: arm64: nv: Support multiple nested Stage-2 mmu structures Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 38/94] KVM: arm64: nv: Implement nested Stage-2 page table walk logic Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 39/94] KVM: arm64: nv: Handle shadow stage 2 page faults Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 40/94] KVM: arm64: nv: Unmap/flush shadow stage 2 page tables Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 41/94] KVM: arm64: nv: Move last_vcpu_ran to be per s2 mmu Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 42/94] KVM: arm64: nv: Introduce sys_reg_desc.forward_trap Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 43/94] KVM: arm64: nv: Set a handler for the system instruction traps Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 44/94] KVM: arm64: nv: Trap and emulate AT instructions from virtual EL2 Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 45/94] KVM: arm64: nv: Trap and emulate TLBI " Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 46/94] KVM: arm64: nv: Fold guest's HCR_EL2 configuration into the host's Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 47/94] KVM: arm64: nv: Handle traps for timer _EL02 and _EL2 sysregs accessors Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 48/94] KVM: arm64: nv: arch_timer: Support hyp timer emulation Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 49/94] KVM: arm64: nv: Propagate CNTVOFF_EL2 to the virtual EL1 timer Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 50/94] KVM: arm64: nv: Load timer before the GIC Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 51/94] KVM: arm64: nv: vgic-v3: Take cpu_if pointer directly instead of vcpu Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 52/94] KVM: arm64: nv: Nested GICv3 Support Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 53/94] KVM: arm64: nv: vgic: Emulate the HW bit in software Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 54/94] KVM: arm64: nv: vgic: Allow userland to set VGIC maintenance IRQ Marc Zyngier
2020-02-11 17:48 ` [PATCH v2 55/94] KVM: arm64: nv: Implement maintenance interrupt forwarding Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 56/94] KVM: arm64: nv: Add nested GICv3 tracepoints Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 57/94] arm64: KVM: nv: Add handling of EL2-specific timer registers Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 58/94] arm64: KVM: nv: Honor SCTLR_EL2.SPAN on entering vEL2 Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 59/94] arm64: KVM: nv: Handle SCTLR_EL2 RES0/RES1 bits Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 60/94] arm64: KVM: nv: Restrict S2 RD/WR permissions to match the guest's Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 61/94] arm64: KVM: nv: Allow userspace to request KVM_ARM_VCPU_NESTED_VIRT Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 62/94] arm64: Detect the ARMv8.4 TTL feature Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 63/94] arm64: KVM: nv: Add handling of ARMv8.4-TTL TLB invalidation Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 64/94] arm64: KVM: nv: Invalidate TLBs based on shadow S2 TTL-like information Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 65/94] arm64: KVM: nv: Tag shadow S2 entries with nested level Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 66/94] arm64: Add SW reserved PTE/PMD bits Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 67/94] arm64: Add level-hinted TLB invalidation helper Marc Zyngier
2020-03-25 10:38   ` Zhenyu Ye
2020-03-25 11:28     ` Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 68/94] arm64: KVM: Add a level hint to __kvm_tlb_flush_vmid_ipa Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 69/94] arm64: KVM: Use TTL hint in when invalidating stage-2 translations Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 70/94] arm64: KVM: nv: Add include containing the VNCR_EL2 offsets Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 71/94] KVM: arm64: Introduce accessor for ctxt->sys_reg Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 72/94] KVM: arm64: sysreg: Use ctxt_sys_reg() instead of raw sys_regs access Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 73/94] KVM: arm64: sve: Use __vcpu_sys_reg() " Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 74/94] KVM: arm64: pauth: Use ctxt_sys_reg() " Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 75/94] KVM: arm64: debug: " Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 76/94] KVM: arm64: Add missing reset handlers for PMU emulation Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 77/94] KVM: arm64: nv: Move sysreg reset check to boot time Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 78/94] KVM: arm64: Map VNCR-capable registers to a separate page Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 79/94] KVM: arm64: nv: Move nested vgic state into the sysreg file Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 80/94] KVM: arm64: Use accessors for timer ctl/cval/offset Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 81/94] KVM: arm64: Add VNCR-capable timer accessors for arm64 Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 82/94] KVM: arm64: Make struct kvm_regs userspace-only Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 83/94] KVM: arm64: VNCR-ize ELR_EL1 Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 84/94] KVM: arm64: VNCR-ize SP_EL1 Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 85/94] KVM: arm64: Disintegrate SPSR array Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 86/94] KVM: arm64: aarch32: Use __vcpu_sys_reg() instead of raw sys_regs access Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 87/94] KVM: arm64: VNCR-ize SPSR_EL1 Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 88/94] KVM: arm64: Add ARMv8.4 Enhanced Nested Virt cpufeature Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 89/94] KVM: arm64: nv: Synchronize PSTATE early on exit Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 90/94] KVM: arm64: nv: Sync nested timer state with ARMv8.4 Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 91/94] KVM: arm64: nv: Allocate VNCR page when required Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 92/94] KVM: arm64: nv: Enable ARMv8.4-NV support Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 93/94] KVM: arm64: nv: Fast-track 'InHost' exception returns Marc Zyngier
2020-02-11 17:49 ` [PATCH v2 94/94] KVM: arm64: nv: Fast-track EL1 TLBIs for VHE guests Marc Zyngier

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