From: Will Deacon <will@kernel.org>
To: Quentin Perret <qperret@google.com>
Cc: catalin.marinas@arm.com, maz@kernel.org, james.morse@arm.com,
julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com,
android-kvm@google.com, linux-kernel@vger.kernel.org,
kernel-team@android.com, kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org, tabba@google.com,
mark.rutland@arm.com, dbrazdil@google.com, mate.toth-pal@arm.com,
seanjc@google.com, robh+dt@kernel.org
Subject: Re: [PATCH v3 16/32] KVM: arm64: Elevate hypervisor mappings creation at EL2
Date: Thu, 4 Mar 2021 19:25:41 +0000 [thread overview]
Message-ID: <20210304192540.GE21795@willie-the-truck> (raw)
In-Reply-To: <20210302150002.3685113-17-qperret@google.com>
On Tue, Mar 02, 2021 at 02:59:46PM +0000, Quentin Perret wrote:
> Previous commits have introduced infrastructure to enable the EL2 code
> to manage its own stage 1 mappings. However, this was preliminary work,
> and none of it is currently in use.
>
> Put all of this together by elevating the mapping creation at EL2 when
> memory protection is enabled. In this case, the host kernel running
> at EL1 still creates _temporary_ EL2 mappings, only used while
> initializing the hypervisor, but frees them right after.
>
> As such, all calls to create_hyp_mappings() after kvm init has finished
> turn into hypercalls, as the host now has no 'legal' way to modify the
> hypevisor page tables directly.
>
> Signed-off-by: Quentin Perret <qperret@google.com>
> ---
> arch/arm64/include/asm/kvm_mmu.h | 2 +-
> arch/arm64/kvm/arm.c | 87 +++++++++++++++++++++++++++++---
> arch/arm64/kvm/mmu.c | 43 ++++++++++++++--
> 3 files changed, 120 insertions(+), 12 deletions(-)
[...]
> @@ -1489,13 +1497,14 @@ static void cpu_hyp_reinit(void)
> kvm_init_host_cpu_context(&this_cpu_ptr_hyp_sym(kvm_host_data)->host_ctxt);
>
> cpu_hyp_reset();
> - cpu_set_hyp_vector();
>
> if (is_kernel_in_hyp_mode())
> kvm_timer_init_vhe();
> else
> cpu_init_hyp_mode();
>
> + cpu_set_hyp_vector();
> +
> kvm_arm_init_debug();
>
> if (vgic_present)
> @@ -1691,18 +1700,59 @@ static void teardown_hyp_mode(void)
> }
> }
>
> +static int do_pkvm_init(u32 hyp_va_bits)
> +{
> + void *per_cpu_base = kvm_ksym_ref(kvm_arm_hyp_percpu_base);
> + int ret;
> +
> + preempt_disable();
> + hyp_install_host_vector();
It's a shame we need this both here _and_ on the reinit path, but it looks
like it's necessary.
> + ret = kvm_call_hyp_nvhe(__pkvm_init, hyp_mem_base, hyp_mem_size,
> + num_possible_cpus(), kern_hyp_va(per_cpu_base),
> + hyp_va_bits);
> + preempt_enable();
> +
> + return ret;
> +}
[...]
> /**
> * Inits Hyp-mode on all online CPUs
> */
> static int init_hyp_mode(void)
> {
> + u32 hyp_va_bits;
> int cpu;
> - int err = 0;
> + int err = -ENOMEM;
> +
> + /*
> + * The protected Hyp-mode cannot be initialized if the memory pool
> + * allocation has failed.
> + */
> + if (is_protected_kvm_enabled() && !hyp_mem_base)
> + return err;
This skips the error message you get on the out_err path.
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index 4d41d7838d53..9d331bf262d2 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -221,15 +221,39 @@ void free_hyp_pgds(void)
> if (hyp_pgtable) {
> kvm_pgtable_hyp_destroy(hyp_pgtable);
> kfree(hyp_pgtable);
> + hyp_pgtable = NULL;
> }
> mutex_unlock(&kvm_hyp_pgd_mutex);
> }
>
> +static bool kvm_host_owns_hyp_mappings(void)
> +{
> + if (static_branch_likely(&kvm_protected_mode_initialized))
> + return false;
> +
> + /*
> + * This can happen at boot time when __create_hyp_mappings() is called
> + * after the hyp protection has been enabled, but the static key has
> + * not been flipped yet.
> + */
> + if (!hyp_pgtable && is_protected_kvm_enabled())
> + return false;
> +
> + WARN_ON(!hyp_pgtable);
> +
> + return true;
return !(WARN_ON(!hyp_pgtable) && is_protected_kvm_enabled());
?
Will
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next prev parent reply other threads:[~2021-03-04 19:27 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-02 14:59 [PATCH v3 00/32] KVM: arm64: A stage 2 for the host Quentin Perret
2021-03-02 14:59 ` [PATCH v3 01/32] arm64: lib: Annotate {clear, copy}_page() as position-independent Quentin Perret
2021-03-02 14:59 ` [PATCH v3 02/32] KVM: arm64: Link position-independent string routines into .hyp.text Quentin Perret
2021-03-02 14:59 ` [PATCH v3 03/32] arm64: kvm: Add standalone ticket spinlock implementation for use at hyp Quentin Perret
2021-03-02 14:59 ` [PATCH v3 04/32] KVM: arm64: Initialize kvm_nvhe_init_params early Quentin Perret
2021-03-04 13:39 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 05/32] KVM: arm64: Avoid free_page() in page-table allocator Quentin Perret
2021-03-02 14:59 ` [PATCH v3 06/32] KVM: arm64: Factor memory allocation out of pgtable.c Quentin Perret
2021-03-04 14:06 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 07/32] KVM: arm64: Introduce a BSS section for use at Hyp Quentin Perret
2021-03-04 14:09 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 08/32] KVM: arm64: Make kvm_call_hyp() a function call " Quentin Perret
2021-03-02 14:59 ` [PATCH v3 09/32] KVM: arm64: Allow using kvm_nvhe_sym() in hyp code Quentin Perret
2021-03-02 14:59 ` [PATCH v3 10/32] KVM: arm64: Introduce an early Hyp page allocator Quentin Perret
2021-03-04 14:38 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 11/32] KVM: arm64: Stub CONFIG_DEBUG_LIST at Hyp Quentin Perret
2021-03-02 14:59 ` [PATCH v3 12/32] KVM: arm64: Introduce a Hyp buddy page allocator Quentin Perret
2021-03-04 15:30 ` Will Deacon
2021-03-04 15:49 ` Quentin Perret
2021-03-02 14:59 ` [PATCH v3 13/32] KVM: arm64: Enable access to sanitized CPU features at EL2 Quentin Perret
2021-03-02 14:59 ` [PATCH v3 14/32] KVM: arm64: Factor out vector address calculation Quentin Perret
2021-03-02 14:59 ` [PATCH v3 15/32] KVM: arm64: Prepare the creation of s1 mappings at EL2 Quentin Perret
2021-03-04 18:47 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 16/32] KVM: arm64: Elevate hypervisor mappings creation " Quentin Perret
2021-03-04 19:25 ` Will Deacon [this message]
2021-03-05 9:14 ` Quentin Perret
2021-03-02 14:59 ` [PATCH v3 17/32] KVM: arm64: Use kvm_arch for stage 2 pgtable Quentin Perret
2021-03-02 14:59 ` [PATCH v3 18/32] KVM: arm64: Use kvm_arch in kvm_s2_mmu Quentin Perret
2021-03-02 14:59 ` [PATCH v3 19/32] KVM: arm64: Set host stage 2 using kvm_nvhe_init_params Quentin Perret
2021-03-02 14:59 ` [PATCH v3 20/32] KVM: arm64: Refactor kvm_arm_setup_stage2() Quentin Perret
2021-03-04 19:35 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 21/32] KVM: arm64: Refactor __load_guest_stage2() Quentin Perret
2021-03-02 14:59 ` [PATCH v3 22/32] KVM: arm64: Refactor __populate_fault_info() Quentin Perret
2021-03-04 19:39 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 23/32] KVM: arm64: Make memcache anonymous in pgtable allocator Quentin Perret
2021-03-04 19:44 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 24/32] KVM: arm64: Reserve memory for host stage 2 Quentin Perret
2021-03-04 19:49 ` Will Deacon
2021-03-05 9:17 ` Quentin Perret
2021-03-02 14:59 ` [PATCH v3 25/32] KVM: arm64: Sort the hypervisor memblocks Quentin Perret
2021-03-04 19:51 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 26/32] KVM: arm64: Introduce PROT_NONE mappings for stage 2 Quentin Perret
2021-03-04 20:00 ` Will Deacon
2021-03-05 9:52 ` Quentin Perret
2021-03-05 19:03 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 27/32] KVM: arm64: Refactor stage2_map_set_prot_attr() Quentin Perret
2021-03-04 20:03 ` Will Deacon
2021-03-05 9:18 ` Quentin Perret
2021-03-02 14:59 ` [PATCH v3 28/32] KVM: arm64: Add kvm_pgtable_stage2_idmap_greedy() Quentin Perret
2021-03-05 14:39 ` Will Deacon
2021-03-05 15:03 ` Quentin Perret
2021-03-05 16:59 ` Will Deacon
2021-03-02 14:59 ` [PATCH v3 29/32] KVM: arm64: Wrap the host with a stage 2 Quentin Perret
2021-03-05 19:29 ` Will Deacon
2021-03-08 9:22 ` Quentin Perret
2021-03-08 12:46 ` Will Deacon
2021-03-08 13:38 ` Quentin Perret
2021-03-08 13:52 ` Will Deacon
2021-03-02 15:00 ` [PATCH v3 30/32] KVM: arm64: Page-align the .hyp sections Quentin Perret
2021-03-04 20:05 ` Will Deacon
2021-03-02 15:00 ` [PATCH v3 31/32] KVM: arm64: Disable PMU support in protected mode Quentin Perret
2021-03-05 19:02 ` Will Deacon
2021-03-02 15:00 ` [PATCH v3 32/32] KVM: arm64: Protect the .hyp sections from the host Quentin Perret
2021-03-05 19:13 ` Will Deacon
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