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From: Alexandru Elisei <alexandru.elisei@arm.com>
To: Marc Zyngier <marc.zyngier@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: Andre Przywara <andre.przywara@arm.com>,
	Dave Martin <Dave.Martin@arm.com>
Subject: Re: [PATCH 33/59] KVM: arm64: nv: Pretend we only support larger-than-host page sizes
Date: Wed, 3 Jul 2019 15:13:07 +0100
Message-ID: <f99c2f11-a59c-485f-a264-69848e1e40c7@arm.com> (raw)
In-Reply-To: <20190621093843.220980-34-marc.zyngier@arm.com>


On 6/21/19 10:38 AM, Marc Zyngier wrote:
> From: Jintack Lim <jintack.lim@linaro.org>
>
> Exposing memory management support to the virtual EL2 as is exposed to
> the host hypervisor would make the implementation too complex and
> inefficient. Therefore expose limited memory management support for the
> following two cases.
>
> We expose same or larger page granules than the one host uses.  We can
> theoretically support a guest hypervisor having smaller-than-host
> granularities but it is not worth it since it makes the implementation
> complicated and it would waste memory.
>
> We expose 40 bits of physical address range to the virtual EL2, because
> we only support a 40bit IPA for the guest. Eventually, this will change.
>
>   [ This was only trapping on the 32-bit encoding, also using the
>     current target register value as a base for the sanitisation.
>
>     Use as the handler for the 64-bit sysreg as well, also load the
>     sanitised version of the sysreg before clearing and setting bits.
>
>     -- Andre Przywara ]
>
> Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  arch/arm64/kvm/sys_regs.c | 50 ++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 49 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index ec34b81da936..cc994ec3c121 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -1710,6 +1710,54 @@ static bool access_spsr_el2(struct kvm_vcpu *vcpu,
>  	return true;
>  }
>  
> +static bool access_id_aa64mmfr0_el1(struct kvm_vcpu *v,
> +				    struct sys_reg_params *p,
> +				    const struct sys_reg_desc *r)
> +{
> +	u64 val;
> +
> +	if (p->is_write)
> +		return write_to_read_only(v, p, r);
> +
> +	val = read_id_reg(v, r, false);
> +
> +	if (!nested_virt_in_use(v))
> +		goto out;
> +
> +	/*
> +	 * Don't expose granules smaller than the host's granule to the guest.
> +	 * We can theoretically support a guest hypervisor having
> +	 * smaller-than-host granularities but it is not worth it since it
> +	 * makes the implementation complicated and it would waste memory.
> +	 */
> +	switch (PAGE_SIZE) {
> +	case SZ_64K:
> +		/* 16KB granule not supported */
> +		val &= ~(0xf << ID_AA64MMFR0_TGRAN16_SHIFT);
> +		val |= (ID_AA64MMFR0_TGRAN16_NI << ID_AA64MMFR0_TGRAN16_SHIFT);
> +		/* fall through */
> +	case SZ_16K:
> +		/* 4KB granule not supported */
> +		val &= ~(0xf << ID_AA64MMFR0_TGRAN4_SHIFT);
> +		val |= (ID_AA64MMFR0_TGRAN4_NI << ID_AA64MMFR0_TGRAN4_SHIFT);
> +		break;
> +	case SZ_4K:
> +		/* All granule sizes are supported */
> +		break;
> +	default:
> +		unreachable();
> +	}
> +
> +	/* Expose only 40 bits physical address range to the guest hypervisor */
> +	val &= ~(0xf << ID_AA64MMFR0_PARANGE_SHIFT);
> +	val |= (0x2 << ID_AA64MMFR0_PARANGE_SHIFT); /* 40 bits */

There are already defines for ID_AA64MMFR0_PARANGE_48 and
ID_AA64MMFR0_PARANGE_52 in sysreg.h, perhaps a similar define for
ID_AA64MMFR0_PARANGE_40 would be appropriate?

> +
> +out:
> +	p->regval = val;
> +
> +	return true;
> +}
> +
>  static bool access_id_aa64pfr0_el1(struct kvm_vcpu *v,
>  				   struct sys_reg_params *p,
>  				   const struct sys_reg_desc *r)
> @@ -1846,7 +1894,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
>  	ID_UNALLOCATED(6,7),
>  
>  	/* CRm=7 */
> -	ID_SANITISED(ID_AA64MMFR0_EL1),
> +	ID_SANITISED_FN(ID_AA64MMFR0_EL1, access_id_aa64mmfr0_el1),
>  	ID_SANITISED(ID_AA64MMFR1_EL1),
>  	ID_SANITISED(ID_AA64MMFR2_EL1),
>  	ID_UNALLOCATED(7,3),

  reply index

Thread overview: 174+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-21  9:37 [PATCH 00/59] KVM: arm64: ARMv8.3 Nested Virtualization support Marc Zyngier
2019-06-21  9:37 ` [PATCH 01/59] KVM: arm64: Migrate _elx sysreg accessors to msr_s/mrs_s Marc Zyngier
2019-06-24 11:16   ` Dave Martin
2019-06-24 12:59   ` Alexandru Elisei
2019-07-03 12:32     ` Marc Zyngier
2019-06-21  9:37 ` [PATCH 02/59] KVM: arm64: Move __load_guest_stage2 to kvm_mmu.h Marc Zyngier
2019-06-24 11:19   ` Dave Martin
2019-07-03  9:30     ` Marc Zyngier
2019-07-03 16:13       ` Dave Martin
2019-06-21  9:37 ` [PATCH 03/59] arm64: Add ARM64_HAS_NESTED_VIRT cpufeature Marc Zyngier
2019-06-21 13:08   ` Julien Thierry
2019-06-21 13:22     ` Marc Zyngier
2019-06-21 13:44   ` Suzuki K Poulose
2019-06-24 11:24   ` Dave Martin
2019-06-21  9:37 ` [PATCH 04/59] KVM: arm64: nv: Introduce nested virtualization VCPU feature Marc Zyngier
2019-06-21 13:08   ` Julien Thierry
2019-06-24 11:28   ` Dave Martin
2019-07-03 11:53     ` Marc Zyngier
2019-07-03 16:27       ` Dave Martin
2019-06-24 11:43   ` Dave Martin
2019-07-03 11:56     ` Marc Zyngier
2019-07-03 16:24       ` Dave Martin
2019-06-21  9:37 ` [PATCH 05/59] KVM: arm64: nv: Reset VCPU to EL2 registers if VCPU nested virt is set Marc Zyngier
2019-06-24 10:19   ` Suzuki K Poulose
2019-06-24 11:38   ` Dave Martin
2019-06-21  9:37 ` [PATCH 06/59] KVM: arm64: nv: Allow userspace to set PSR_MODE_EL2x Marc Zyngier
2019-06-21 13:24   ` Julien Thierry
2019-06-21 13:50     ` Marc Zyngier
2019-06-24 12:48       ` Dave Martin
2019-07-03  9:21         ` Marc Zyngier
2019-07-04 10:00           ` Dave Martin
2019-06-21  9:37 ` [PATCH 07/59] KVM: arm64: nv: Add EL2 system registers to vcpu context Marc Zyngier
2019-06-24 12:54   ` Dave Martin
2019-07-03 12:20     ` Marc Zyngier
2019-07-03 16:31       ` Dave Martin
2019-06-24 15:47   ` Alexandru Elisei
2019-07-03 13:20     ` Marc Zyngier
2019-07-03 16:01       ` Marc Zyngier
2019-07-01 16:36   ` Suzuki K Poulose
2019-06-21  9:37 ` [PATCH 08/59] KVM: arm64: nv: Reset VMPIDR_EL2 and VPIDR_EL2 to sane values Marc Zyngier
2019-06-24 12:59   ` Dave Martin
2019-06-21  9:37 ` [PATCH 09/59] KVM: arm64: nv: Add nested virt VCPU primitives for vEL2 VCPU state Marc Zyngier
2019-06-24 13:08   ` Dave Martin
2019-06-21  9:37 ` [PATCH 10/59] KVM: arm64: nv: Support virtual EL2 exceptions Marc Zyngier
2019-07-08 13:56   ` Steven Price
2019-06-21  9:37 ` [PATCH 11/59] KVM: arm64: nv: Inject HVC exceptions to the virtual EL2 Marc Zyngier
2019-06-25 13:13   ` Alexandru Elisei
2019-07-03 14:16     ` Marc Zyngier
2019-07-30 14:08     ` Alexandru Elisei
2019-06-21  9:37 ` [PATCH 12/59] KVM: arm64: nv: Handle trapped ERET from " Marc Zyngier
2019-07-02 12:00   ` Alexandru Elisei
2019-06-21  9:37 ` [PATCH 13/59] KVM: arm64: nv: Handle virtual EL2 registers in vcpu_read/write_sys_reg() Marc Zyngier
2019-06-24 12:42   ` Julien Thierry
2019-06-25 14:02     ` Alexandru Elisei
2019-07-03 12:15     ` Marc Zyngier
2019-07-03 15:21       ` Julien Thierry
2019-06-25 15:18   ` Alexandru Elisei
2019-07-01  9:58     ` Alexandru Elisei
2019-07-03 15:59     ` Marc Zyngier
2019-07-03 16:32       ` Alexandru Elisei
2019-07-04 14:39         ` Marc Zyngier
2019-06-26 15:04   ` Alexandru Elisei
2019-07-04 15:05     ` Marc Zyngier
2019-07-01 12:10   ` Alexandru Elisei
2019-06-21  9:37 ` [PATCH 14/59] KVM: arm64: nv: Handle SPSR_EL2 specially Marc Zyngier
2019-06-21  9:37 ` [PATCH 15/59] KVM: arm64: nv: Refactor vcpu_{read,write}_sys_reg Marc Zyngier
2019-06-24 15:07   ` Julien Thierry
2019-07-03 13:09     ` Marc Zyngier
2019-06-27  9:21   ` Alexandru Elisei
2019-07-04 15:15     ` Marc Zyngier
2019-06-21  9:38 ` [PATCH 16/59] KVM: arm64: nv: Save/Restore vEL2 sysregs Marc Zyngier
2019-06-25  8:48   ` Julien Thierry
2019-07-03 13:42     ` Marc Zyngier
2019-07-01 12:09   ` Alexandru Elisei
2019-08-21 11:57   ` Alexandru Elisei
2019-06-21  9:38 ` [PATCH 17/59] KVM: arm64: nv: Emulate PSTATE.M for a guest hypervisor Marc Zyngier
2019-06-21  9:38 ` [PATCH 18/59] KVM: arm64: nv: Trap EL1 VM register accesses in virtual EL2 Marc Zyngier
2019-07-01 16:12   ` Alexandru Elisei
2019-06-21  9:38 ` [PATCH 19/59] KVM: arm64: nv: Trap SPSR_EL1, ELR_EL1 and VBAR_EL1 from " Marc Zyngier
2019-06-21  9:38 ` [PATCH 20/59] KVM: arm64: nv: Trap CPACR_EL1 access in " Marc Zyngier
2019-07-01 16:40   ` Alexandru Elisei
2019-06-21  9:38 ` [PATCH 21/59] KVM: arm64: nv: Set a handler for the system instruction traps Marc Zyngier
2019-06-25 12:55   ` Julien Thierry
2019-07-03 14:15     ` Marc Zyngier
2019-06-21  9:38 ` [PATCH 22/59] KVM: arm64: nv: Handle PSCI call via smc from the guest Marc Zyngier
2019-06-21  9:38 ` [PATCH 23/59] KVM: arm64: nv: Respect virtual HCR_EL2.TWX setting Marc Zyngier
2019-06-25 14:19   ` Julien Thierry
2019-07-02 12:54     ` Alexandru Elisei
2019-07-03 14:18     ` Marc Zyngier
2019-06-21  9:38 ` [PATCH 24/59] KVM: arm64: nv: Respect virtual CPTR_EL2.TFP setting Marc Zyngier
2019-06-21  9:38 ` [PATCH 25/59] KVM: arm64: nv: Don't expose SVE to nested guests Marc Zyngier
2019-06-21  9:38 ` [PATCH 26/59] KVM: arm64: nv: Respect the virtual HCR_EL2.NV bit setting Marc Zyngier
2019-06-26  5:31   ` Julien Thierry
2019-07-03 16:31     ` Marc Zyngier
2019-06-21  9:38 ` [PATCH 27/59] KVM: arm64: nv: Respect virtual HCR_EL2.TVM and TRVM settings Marc Zyngier
2019-06-26  6:55   ` Julien Thierry
2019-07-04 14:57     ` Marc Zyngier
2019-06-21  9:38 ` [PATCH 28/59] KVM: arm64: nv: Respect the virtual HCR_EL2.NV1 bit setting Marc Zyngier
2019-06-26  7:23   ` Julien Thierry
2019-07-02 16:32   ` Alexandru Elisei
2019-07-03  9:10     ` Alexandru Elisei
2019-06-21  9:38 ` [PATCH 29/59] KVM: arm64: nv: Emulate EL12 register accesses from the virtual EL2 Marc Zyngier
2019-07-03  9:16   ` Alexandru Elisei
2019-06-21  9:38 ` [PATCH 30/59] KVM: arm64: nv: Configure HCR_EL2 for nested virtualization Marc Zyngier
2019-06-21  9:38 ` [PATCH 31/59] KVM: arm64: nv: Only toggle cache for virtual EL2 when SCTLR_EL2 changes Marc Zyngier
2019-06-21  9:38 ` [PATCH 32/59] KVM: arm64: nv: Hide RAS from nested guests Marc Zyngier
2019-07-03 13:59   ` Alexandru Elisei
2019-06-21  9:38 ` [PATCH 33/59] KVM: arm64: nv: Pretend we only support larger-than-host page sizes Marc Zyngier
2019-07-03 14:13   ` Alexandru Elisei [this message]
2019-06-21  9:38 ` [PATCH 34/59] KVM: arm/arm64: nv: Factor out stage 2 page table data from struct kvm Marc Zyngier
2019-07-03 15:52   ` Alexandru Elisei
2019-06-21  9:38 ` [PATCH 35/59] KVM: arm/arm64: nv: Support multiple nested stage 2 mmu structures Marc Zyngier
2019-06-25 12:19   ` Alexandru Elisei
2019-07-03 13:47     ` Marc Zyngier
2019-06-27 13:15   ` Julien Thierry
2019-07-04 15:51   ` Alexandru Elisei
2019-06-21  9:38 ` [PATCH 36/59] KVM: arm64: nv: Implement nested Stage-2 page table walk logic Marc Zyngier
2019-06-21  9:38 ` [PATCH 37/59] KVM: arm64: nv: Handle shadow stage 2 page faults Marc Zyngier
2019-07-05 14:28   ` Alexandru Elisei
2019-06-21  9:38 ` [PATCH 38/59] KVM: arm64: nv: Unmap/flush shadow stage 2 page tables Marc Zyngier
2019-07-01  8:03   ` Julien Thierry
2019-06-21  9:38 ` [PATCH 39/59] KVM: arm64: nv: Move last_vcpu_ran to be per s2 mmu Marc Zyngier
2019-07-01  9:10   ` Julien Thierry
2019-07-05 15:28   ` Alexandru Elisei
2019-06-21  9:38 ` [PATCH 40/59] KVM: arm64: nv: Don't always start an S2 MMU search from the beginning Marc Zyngier
2019-07-09  9:59   ` Alexandru Elisei
2019-06-21  9:38 ` [PATCH 41/59] KVM: arm64: nv: Introduce sys_reg_desc.forward_trap Marc Zyngier
2019-06-21  9:38 ` [PATCH 42/59] KVM: arm64: nv: Rework the system instruction emulation framework Marc Zyngier
2019-06-21  9:38 ` [PATCH 43/59] KVM: arm64: nv: Trap and emulate AT instructions from virtual EL2 Marc Zyngier
2019-07-01 15:45   ` Julien Thierry
2019-07-09 13:20   ` Alexandru Elisei
2019-07-18 12:13     ` Tomasz Nowicki
     [not found]       ` <6537c8d2-3bda-788e-8861-b70971a625cb@arm.com>
2019-07-18 12:59         ` Tomasz Nowicki
2019-07-24 10:25   ` Tomasz Nowicki
2019-07-24 12:39     ` Marc Zyngier
2019-07-24 13:56       ` Tomasz Nowicki
2019-06-21  9:38 ` [PATCH 44/59] KVM: arm64: nv: Trap and emulate TLBI " Marc Zyngier
2019-07-02 12:37   ` Julien Thierry
2019-07-10 10:15   ` Alexandru Elisei
2019-06-21  9:38 ` [PATCH 45/59] KVM: arm64: nv: Handle traps for timer _EL02 and _EL2 sysregs accessors Marc Zyngier
2019-06-21  9:38 ` [PATCH 46/59] KVM: arm64: nv: arch_timer: Support hyp timer emulation Marc Zyngier
2019-07-10 16:23   ` Alexandru Elisei
2019-06-21  9:38 ` [PATCH 47/59] KVM: arm64: nv: Propagate CNTVOFF_EL2 to the virtual EL1 timer Marc Zyngier
2019-08-08  9:34   ` Alexandru Elisei
2019-06-21  9:38 ` [PATCH 48/59] KVM: arm64: nv: Load timer before the GIC Marc Zyngier
2019-07-11 13:17   ` Alexandru Elisei
2019-06-21  9:38 ` [PATCH 49/59] KVM: arm64: nv: vgic-v3: Take cpu_if pointer directly instead of vcpu Marc Zyngier
2019-06-21  9:38 ` [PATCH 50/59] KVM: arm64: nv: Nested GICv3 Support Marc Zyngier
2019-07-16 11:41   ` Alexandru Elisei
2019-06-21  9:38 ` [PATCH 51/59] KVM: arm64: nv: vgic: Emulate the HW bit in software Marc Zyngier
2019-06-21  9:38 ` [PATCH 52/59] KVM: arm64: nv: vgic: Allow userland to set VGIC maintenance IRQ Marc Zyngier
2019-07-04  7:38   ` Julien Thierry
2019-07-04  9:01     ` Andre Przywara
2019-07-04  9:04       ` Julien Thierry
2019-06-21  9:38 ` [PATCH 53/59] KVM: arm64: nv: Implement maintenance interrupt forwarding Marc Zyngier
2019-07-04  8:06   ` Julien Thierry
2019-07-16 16:35   ` Alexandru Elisei
2019-06-21  9:38 ` [PATCH 54/59] KVM: arm64: nv: Add nested GICv3 tracepoints Marc Zyngier
2019-06-21  9:38 ` [PATCH 55/59] arm64: KVM: nv: Add handling of EL2-specific timer registers Marc Zyngier
2019-07-11 12:35   ` Alexandru Elisei
2019-07-17 10:19   ` Alexandru Elisei
2019-06-21  9:38 ` [PATCH 56/59] arm64: KVM: nv: Honor SCTLR_EL2.SPAN on entering vEL2 Marc Zyngier
2019-06-21  9:38 ` [PATCH 57/59] arm64: KVM: nv: Handle SCTLR_EL2 RES0/RES1 bits Marc Zyngier
2019-06-21  9:38 ` [PATCH 58/59] arm64: KVM: nv: Restrict S2 RD/WR permissions to match the guest's Marc Zyngier
2019-06-21  9:38 ` [PATCH 59/59] arm64: KVM: nv: Allow userspace to request KVM_ARM_VCPU_NESTED_VIRT Marc Zyngier
     [not found] ` <CANW9uyssDm_0ysC_pnvhHRrnsmFZik+3_ENmFz7L2GCmtH09fw@mail.gmail.com>
2019-06-21 11:21   ` [PATCH 00/59] KVM: arm64: ARMv8.3 Nested Virtualization support Marc Zyngier
2019-08-02 10:11 ` Alexandru Elisei
2019-08-02 10:30   ` Andrew Jones
2019-08-09 10:01   ` Alexandru Elisei
2019-08-09 11:44     ` Andrew Jones
2019-08-09 12:00       ` Alexandru Elisei
2019-08-09 13:00         ` Andrew Jones
2019-08-22 11:57     ` Alexandru Elisei
2019-08-22 15:32       ` Alexandru Elisei

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