From: Marc Zyngier <maz@kernel.org>
To: David Brazdil <dbrazdil@google.com>
Cc: kernel-team@android.com,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Andrew Walbran <qwandor@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, Tejun Heo <tj@kernel.org>,
Dennis Zhou <dennis@kernel.org>, Christoph Lameter <cl@linux.com>,
Will Deacon <will@kernel.org>,
kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH v2 23/24] kvm: arm64: Trap host SMCs in protected mode.
Date: Mon, 23 Nov 2020 17:36:16 +0000 [thread overview]
Message-ID: <87d0045627.wl-maz@kernel.org> (raw)
In-Reply-To: <20201116204318.63987-24-dbrazdil@google.com>
On Mon, 16 Nov 2020 20:43:17 +0000,
David Brazdil <dbrazdil@google.com> wrote:
>
> While protected nVHE KVM is installed, start trapping all host SMCs.
> By default, these are simply forwarded to EL3, but PSCI SMCs are
> validated first.
>
> Create new constant HCR_HOST_NVHE_PROTECTED_FLAGS with the new set of HCR
> flags to use while the nVHE vector is installed when the kernel was
> booted with the protected flag enabled. Switch back to the default HCR
> flags when switching back to the stub vector.
>
> Signed-off-by: David Brazdil <dbrazdil@google.com>
> ---
> arch/arm64/include/asm/kvm_arm.h | 1 +
> arch/arm64/kvm/hyp/nvhe/hyp-init.S | 12 ++++++++++++
> arch/arm64/kvm/hyp/nvhe/switch.c | 5 ++++-
> 3 files changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
> index 64ce29378467..4e90c2debf70 100644
> --- a/arch/arm64/include/asm/kvm_arm.h
> +++ b/arch/arm64/include/asm/kvm_arm.h
> @@ -80,6 +80,7 @@
> HCR_FMO | HCR_IMO | HCR_PTW )
> #define HCR_VIRT_EXCP_MASK (HCR_VSE | HCR_VI | HCR_VF)
> #define HCR_HOST_NVHE_FLAGS (HCR_RW | HCR_API | HCR_APK | HCR_ATA)
> +#define HCR_HOST_NVHE_PROTECTED_FLAGS (HCR_HOST_NVHE_FLAGS | HCR_TSC)
> #define HCR_HOST_VHE_FLAGS (HCR_RW | HCR_TGE | HCR_E2H)
>
> /* TCR_EL2 Registers bits */
> diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
> index 6d8202d2bdfb..8f3602f320ac 100644
> --- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S
> +++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
> @@ -88,6 +88,12 @@ SYM_CODE_END(__kvm_hyp_init)
> * x0: struct kvm_nvhe_init_params PA
> */
> SYM_CODE_START(___kvm_hyp_init)
> +alternative_if ARM64_PROTECTED_KVM
> + mov_q x1, HCR_HOST_NVHE_PROTECTED_FLAGS
> + msr hcr_el2, x1
> + isb
Why the ISB? For HCR_TSC to have any effect, you'll have to go via an
ERET to EL1 first, which will have the required synchronisation effect.
> +alternative_else_nop_endif
> +
> ldr x1, [x0, #NVHE_INIT_TPIDR_EL2]
> msr tpidr_el2, x1
>
> @@ -224,6 +230,12 @@ reset:
> msr sctlr_el2, x5
> isb
>
> +alternative_if ARM64_PROTECTED_KVM
> + mov_q x5, HCR_HOST_NVHE_FLAGS
> + msr hcr_el2, x5
> + isb
Same thing here, I believe.
> +alternative_else_nop_endif
> +
> /* Install stub vectors */
> adr_l x5, __hyp_stub_vectors
> msr vbar_el2, x5
> diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
> index 8ae8160bc93a..e1f8e0797144 100644
> --- a/arch/arm64/kvm/hyp/nvhe/switch.c
> +++ b/arch/arm64/kvm/hyp/nvhe/switch.c
> @@ -96,7 +96,10 @@ static void __deactivate_traps(struct kvm_vcpu *vcpu)
> mdcr_el2 |= MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT;
>
> write_sysreg(mdcr_el2, mdcr_el2);
> - write_sysreg(HCR_HOST_NVHE_FLAGS, hcr_el2);
> + if (is_protected_kvm_enabled())
> + write_sysreg(HCR_HOST_NVHE_PROTECTED_FLAGS, hcr_el2);
> + else
> + write_sysreg(HCR_HOST_NVHE_FLAGS, hcr_el2);
> write_sysreg(CPTR_EL2_DEFAULT, cptr_el2);
> write_sysreg(__kvm_hyp_host_vector, vbar_el2);
> }
> --
> 2.29.2.299.gdc1121823c-goog
>
>
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
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next prev parent reply other threads:[~2020-11-23 17:36 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-16 20:42 [PATCH v2 00/24] Opt-in always-on nVHE hypervisor David Brazdil
2020-11-16 20:42 ` [PATCH v2 01/24] psci: Support psci_ops.get_version for v0.1 David Brazdil
2020-11-16 20:42 ` [PATCH v2 02/24] psci: Accessor for configured PSCI function IDs David Brazdil
2020-11-23 13:47 ` Marc Zyngier
2020-11-16 20:42 ` [PATCH v2 03/24] arm64: Make cpu_logical_map() take unsigned int David Brazdil
2020-11-16 20:42 ` [PATCH v2 04/24] arm64: Move MAIR_EL1_SET to asm/memory.h David Brazdil
2020-11-23 13:52 ` Marc Zyngier
2020-11-25 10:31 ` David Brazdil
2020-11-25 11:21 ` Marc Zyngier
2020-11-25 13:26 ` David Brazdil
2020-11-25 13:33 ` Marc Zyngier
2020-11-16 20:42 ` [PATCH v2 05/24] kvm: arm64: Initialize MAIR_EL2 using a constant David Brazdil
2020-11-16 20:43 ` [PATCH v2 06/24] kvm: arm64: Move hyp-init params to a per-CPU struct David Brazdil
2020-11-23 14:20 ` Marc Zyngier
2020-11-25 10:39 ` David Brazdil
2020-11-25 10:49 ` Marc Zyngier
2020-11-16 20:43 ` [PATCH v2 07/24] kvm: arm64: Refactor handle_trap to use a switch David Brazdil
2020-11-23 14:32 ` Marc Zyngier
2020-11-16 20:43 ` [PATCH v2 08/24] kvm: arm64: Add SMC handler in nVHE EL2 David Brazdil
2020-11-23 18:00 ` Marc Zyngier
2020-11-16 20:43 ` [PATCH v2 09/24] kvm: arm64: Add .hyp.data..ro_after_init ELF section David Brazdil
2020-11-16 20:43 ` [PATCH v2 10/24] kvm: arm64: Support per_cpu_ptr in nVHE hyp code David Brazdil
2020-11-16 20:43 ` [PATCH v2 11/24] kvm: arm64: Create nVHE copy of cpu_logical_map David Brazdil
2020-11-16 20:43 ` [PATCH v2 12/24] kvm: arm64: Bootstrap PSCI SMC handler in nVHE EL2 David Brazdil
2020-11-23 17:55 ` Marc Zyngier
2020-11-16 20:43 ` [PATCH v2 13/24] kvm: arm64: Add offset for hyp VA <-> PA conversion David Brazdil
2020-11-16 20:43 ` [PATCH v2 14/24] kvm: arm64: Forward safe PSCI SMCs coming from host David Brazdil
2020-11-16 20:43 ` [PATCH v2 15/24] kvm: arm64: Extract parts of el2_setup into a macro David Brazdil
2020-11-23 15:27 ` Marc Zyngier
2020-11-25 12:57 ` David Brazdil
2020-11-16 20:43 ` [PATCH v2 16/24] kvm: arm64: Extract __do_hyp_init into a helper function David Brazdil
2020-11-16 20:43 ` [PATCH v2 17/24] kvm: arm64: Add CPU entry point in nVHE hyp David Brazdil
2020-11-16 20:43 ` [PATCH v2 18/24] kvm: arm64: Add function to enter host from KVM nVHE hyp code David Brazdil
2020-11-16 20:43 ` [PATCH v2 19/24] kvm: arm64: Intercept host's PSCI_CPU_ON SMCs David Brazdil
2020-11-23 17:04 ` Marc Zyngier
2020-11-16 20:43 ` [PATCH v2 20/24] kvm: arm64: Intercept host's CPU_SUSPEND PSCI SMCs David Brazdil
2020-11-23 17:22 ` Marc Zyngier
2020-11-16 20:43 ` [PATCH v2 21/24] kvm: arm64: Add kvm-arm.protected early kernel parameter David Brazdil
2020-11-23 17:30 ` Marc Zyngier
2020-11-16 20:43 ` [PATCH v2 22/24] kvm: arm64: Keep nVHE EL2 vector installed David Brazdil
2020-11-16 20:43 ` [PATCH v2 23/24] kvm: arm64: Trap host SMCs in protected mode David Brazdil
2020-11-23 17:36 ` Marc Zyngier [this message]
2020-11-16 20:43 ` [PATCH v2 24/24] kvm: arm64: Fix EL2 mode availability checks David Brazdil
2020-11-23 13:44 ` [PATCH v2 00/24] Opt-in always-on nVHE hypervisor Marc Zyngier
2020-11-23 18:01 ` Marc Zyngier
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