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From: Will Deacon <will@kernel.org>
To: Quentin Perret <qperret@google.com>
Cc: Fuad Tabba <tabba@google.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Rob Herring <robh+dt@kernel.org>,
	Frank Rowand <frowand.list@gmail.com>,
	"moderated list:ARM64 PORT (AARCH64 ARCHITECTURE)" 
	<linux-arm-kernel@lists.infradead.org>,
	open list <linux-kernel@vger.kernel.org>,
	"open list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" 
	<kvmarm@lists.cs.columbia.edu>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE" 
	<devicetree@vger.kernel.org>,
	kernel-team@android.com, Android KVM <android-kvm@google.com>
Subject: Re: [RFC PATCH 16/27] KVM: arm64: Prepare Hyp memory protection
Date: Mon, 7 Dec 2020 10:20:03 +0000	[thread overview]
Message-ID: <20201207102002.GA3825@willie-the-truck> (raw)
In-Reply-To: <X8p5kLSIq2MoQZ24@google.com>

On Fri, Dec 04, 2020 at 06:01:52PM +0000, Quentin Perret wrote:
> On Thursday 03 Dec 2020 at 12:57:33 (+0000), Fuad Tabba wrote:
> <snip>
> > > +int hyp_create_idmap(void);
> > > +int hyp_map_vectors(void);
> > > +int hyp_back_vmemmap(phys_addr_t phys, unsigned long size, phys_addr_t back);
> > > +int hyp_cpu_set_vector(enum arm64_hyp_spectre_vector slot);
> > > +int hyp_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot);
> > > +int __hyp_create_mappings(unsigned long start, unsigned long size,
> > > +                         unsigned long phys, unsigned long prot);
> > > +unsigned long __hyp_create_private_mapping(phys_addr_t phys, size_t size,
> > > +                                          unsigned long prot);
> > > +
> > 
> > nit: I also thought that the hyp_create_mappings function names are a
> > bit confusing, since there's the create_hyp_mappings functions which
> > use the aforementioned *hyp_pgtable.
> 
> Sure, happy to re-name those (and hyp_pgtable above). Any suggestions?
> 
> 
> <snip>
> > > +SYM_FUNC_START(__kvm_init_switch_pgd)
> > > +       /* Turn the MMU off */
> > > +       pre_disable_mmu_workaround
> > > +       mrs     x2, sctlr_el2
> > > +       bic     x3, x2, #SCTLR_ELx_M
> > > +       msr     sctlr_el2, x3
> > > +       isb
> > > +
> > > +       tlbi    alle2
> > > +
> > > +       /* Install the new pgtables */
> > > +       ldr     x3, [x0, #NVHE_INIT_PGD_PA]
> > > +       phys_to_ttbr x4, x3
> > > +alternative_if ARM64_HAS_CNP
> > > +       orr     x4, x4, #TTBR_CNP_BIT
> > > +alternative_else_nop_endif
> > > +       msr     ttbr0_el2, x4
> > > +
> > > +       /* Set the new stack pointer */
> > > +       ldr     x0, [x0, #NVHE_INIT_STACK_HYP_VA]
> > > +       mov     sp, x0
> > > +
> > > +       /* And turn the MMU back on! */
> > > +       dsb     nsh
> > > +       isb
> > > +       msr     sctlr_el2, x2
> > > +       isb
> > > +       ret     x1
> > > +SYM_FUNC_END(__kvm_init_switch_pgd)
> > > +
> > 
> > Should the instruction cache be flushed here (ic iallu), to discard
> > speculatively fetched instructions?
> 
> Hmm, Will? Thoughts?

The I-cache is physically tagged, so not sure what invalidation would
achieve here. Fuad -- what do you think could go wrong specifically?

Will

WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org>
To: Quentin Perret <qperret@google.com>
Cc: "moderated list:ARM64 PORT \(AARCH64 ARCHITECTURE\)"
	<linux-arm-kernel@lists.infradead.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE"
	<devicetree@vger.kernel.org>,
	kernel-team@android.com, Android KVM <android-kvm@google.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	open list <linux-kernel@vger.kernel.org>,
	Rob Herring <robh+dt@kernel.org>, Fuad Tabba <tabba@google.com>,
	Marc Zyngier <maz@kernel.org>,
	Frank Rowand <frowand.list@gmail.com>,
	"open list:KERNEL VIRTUAL MACHINE FOR ARM64 \(KVM/arm64\)"
	<kvmarm@lists.cs.columbia.edu>
Subject: Re: [RFC PATCH 16/27] KVM: arm64: Prepare Hyp memory protection
Date: Mon, 7 Dec 2020 10:20:03 +0000	[thread overview]
Message-ID: <20201207102002.GA3825@willie-the-truck> (raw)
In-Reply-To: <X8p5kLSIq2MoQZ24@google.com>

On Fri, Dec 04, 2020 at 06:01:52PM +0000, Quentin Perret wrote:
> On Thursday 03 Dec 2020 at 12:57:33 (+0000), Fuad Tabba wrote:
> <snip>
> > > +int hyp_create_idmap(void);
> > > +int hyp_map_vectors(void);
> > > +int hyp_back_vmemmap(phys_addr_t phys, unsigned long size, phys_addr_t back);
> > > +int hyp_cpu_set_vector(enum arm64_hyp_spectre_vector slot);
> > > +int hyp_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot);
> > > +int __hyp_create_mappings(unsigned long start, unsigned long size,
> > > +                         unsigned long phys, unsigned long prot);
> > > +unsigned long __hyp_create_private_mapping(phys_addr_t phys, size_t size,
> > > +                                          unsigned long prot);
> > > +
> > 
> > nit: I also thought that the hyp_create_mappings function names are a
> > bit confusing, since there's the create_hyp_mappings functions which
> > use the aforementioned *hyp_pgtable.
> 
> Sure, happy to re-name those (and hyp_pgtable above). Any suggestions?
> 
> 
> <snip>
> > > +SYM_FUNC_START(__kvm_init_switch_pgd)
> > > +       /* Turn the MMU off */
> > > +       pre_disable_mmu_workaround
> > > +       mrs     x2, sctlr_el2
> > > +       bic     x3, x2, #SCTLR_ELx_M
> > > +       msr     sctlr_el2, x3
> > > +       isb
> > > +
> > > +       tlbi    alle2
> > > +
> > > +       /* Install the new pgtables */
> > > +       ldr     x3, [x0, #NVHE_INIT_PGD_PA]
> > > +       phys_to_ttbr x4, x3
> > > +alternative_if ARM64_HAS_CNP
> > > +       orr     x4, x4, #TTBR_CNP_BIT
> > > +alternative_else_nop_endif
> > > +       msr     ttbr0_el2, x4
> > > +
> > > +       /* Set the new stack pointer */
> > > +       ldr     x0, [x0, #NVHE_INIT_STACK_HYP_VA]
> > > +       mov     sp, x0
> > > +
> > > +       /* And turn the MMU back on! */
> > > +       dsb     nsh
> > > +       isb
> > > +       msr     sctlr_el2, x2
> > > +       isb
> > > +       ret     x1
> > > +SYM_FUNC_END(__kvm_init_switch_pgd)
> > > +
> > 
> > Should the instruction cache be flushed here (ic iallu), to discard
> > speculatively fetched instructions?
> 
> Hmm, Will? Thoughts?

The I-cache is physically tagged, so not sure what invalidation would
achieve here. Fuad -- what do you think could go wrong specifically?

Will
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org>
To: Quentin Perret <qperret@google.com>
Cc: "moderated list:ARM64 PORT \(AARCH64 ARCHITECTURE\)"
	<linux-arm-kernel@lists.infradead.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE"
	<devicetree@vger.kernel.org>,
	kernel-team@android.com,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Android KVM <android-kvm@google.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	open list <linux-kernel@vger.kernel.org>,
	Rob Herring <robh+dt@kernel.org>,
	James Morse <james.morse@arm.com>, Fuad Tabba <tabba@google.com>,
	Marc Zyngier <maz@kernel.org>,
	Frank Rowand <frowand.list@gmail.com>,
	"open list:KERNEL VIRTUAL MACHINE FOR ARM64 \(KVM/arm64\)"
	<kvmarm@lists.cs.columbia.edu>,
	Julien Thierry <julien.thierry.kdev@gmail.com>
Subject: Re: [RFC PATCH 16/27] KVM: arm64: Prepare Hyp memory protection
Date: Mon, 7 Dec 2020 10:20:03 +0000	[thread overview]
Message-ID: <20201207102002.GA3825@willie-the-truck> (raw)
In-Reply-To: <X8p5kLSIq2MoQZ24@google.com>

On Fri, Dec 04, 2020 at 06:01:52PM +0000, Quentin Perret wrote:
> On Thursday 03 Dec 2020 at 12:57:33 (+0000), Fuad Tabba wrote:
> <snip>
> > > +int hyp_create_idmap(void);
> > > +int hyp_map_vectors(void);
> > > +int hyp_back_vmemmap(phys_addr_t phys, unsigned long size, phys_addr_t back);
> > > +int hyp_cpu_set_vector(enum arm64_hyp_spectre_vector slot);
> > > +int hyp_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot);
> > > +int __hyp_create_mappings(unsigned long start, unsigned long size,
> > > +                         unsigned long phys, unsigned long prot);
> > > +unsigned long __hyp_create_private_mapping(phys_addr_t phys, size_t size,
> > > +                                          unsigned long prot);
> > > +
> > 
> > nit: I also thought that the hyp_create_mappings function names are a
> > bit confusing, since there's the create_hyp_mappings functions which
> > use the aforementioned *hyp_pgtable.
> 
> Sure, happy to re-name those (and hyp_pgtable above). Any suggestions?
> 
> 
> <snip>
> > > +SYM_FUNC_START(__kvm_init_switch_pgd)
> > > +       /* Turn the MMU off */
> > > +       pre_disable_mmu_workaround
> > > +       mrs     x2, sctlr_el2
> > > +       bic     x3, x2, #SCTLR_ELx_M
> > > +       msr     sctlr_el2, x3
> > > +       isb
> > > +
> > > +       tlbi    alle2
> > > +
> > > +       /* Install the new pgtables */
> > > +       ldr     x3, [x0, #NVHE_INIT_PGD_PA]
> > > +       phys_to_ttbr x4, x3
> > > +alternative_if ARM64_HAS_CNP
> > > +       orr     x4, x4, #TTBR_CNP_BIT
> > > +alternative_else_nop_endif
> > > +       msr     ttbr0_el2, x4
> > > +
> > > +       /* Set the new stack pointer */
> > > +       ldr     x0, [x0, #NVHE_INIT_STACK_HYP_VA]
> > > +       mov     sp, x0
> > > +
> > > +       /* And turn the MMU back on! */
> > > +       dsb     nsh
> > > +       isb
> > > +       msr     sctlr_el2, x2
> > > +       isb
> > > +       ret     x1
> > > +SYM_FUNC_END(__kvm_init_switch_pgd)
> > > +
> > 
> > Should the instruction cache be flushed here (ic iallu), to discard
> > speculatively fetched instructions?
> 
> Hmm, Will? Thoughts?

The I-cache is physically tagged, so not sure what invalidation would
achieve here. Fuad -- what do you think could go wrong specifically?

Will

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2020-12-07 10:21 UTC|newest]

Thread overview: 162+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-17 18:15 [RFC PATCH 00/27] KVM/arm64: A stage 2 for the host Quentin Perret
2020-11-17 18:15 ` Quentin Perret
2020-11-17 18:15 ` Quentin Perret
2020-11-17 18:15 ` [RFC PATCH 01/27] arm64: lib: Annotate {clear,copy}_page() as position-independent Quentin Perret
2020-11-17 18:15   ` [RFC PATCH 01/27] arm64: lib: Annotate {clear, copy}_page() " Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15 ` [RFC PATCH 02/27] KVM: arm64: Link position-independent string routines into .hyp.text Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-23 12:34   ` David Brazdil
2020-11-23 12:34     ` David Brazdil
2020-11-23 12:34     ` David Brazdil
2020-11-23 14:06     ` Quentin Perret
2020-11-23 14:06       ` Quentin Perret
2020-11-23 14:06       ` Quentin Perret
2020-11-17 18:15 ` [RFC PATCH 03/27] KVM: arm64: Add standalone ticket spinlock implementation for use at hyp Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15 ` [RFC PATCH 04/27] KVM: arm64: Initialize kvm_nvhe_init_params early Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15 ` [RFC PATCH 05/27] KVM: arm64: Avoid free_page() in page-table allocator Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15 ` [RFC PATCH 06/27] KVM: arm64: Factor memory allocation out of pgtable.c Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15 ` [RFC PATCH 07/27] KVM: arm64: Introduce a BSS section for use at Hyp Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15 ` [RFC PATCH 08/27] KVM: arm64: Make kvm_call_hyp() a function call " Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-23 12:51   ` David Brazdil
2020-11-23 12:51     ` David Brazdil
2020-11-23 12:51     ` David Brazdil
2020-11-17 18:15 ` [RFC PATCH 09/27] KVM: arm64: Allow using kvm_nvhe_sym() in hyp code Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-23 12:57   ` David Brazdil
2020-11-23 12:57     ` David Brazdil
2020-11-23 12:57     ` David Brazdil
2020-11-23 14:02     ` Quentin Perret
2020-11-23 14:02       ` Quentin Perret
2020-11-23 14:02       ` Quentin Perret
2020-11-23 14:54       ` David Brazdil
2020-11-23 14:54         ` David Brazdil
2020-11-23 14:54         ` David Brazdil
2020-11-17 18:15 ` [RFC PATCH 10/27] KVM: arm64: Introduce an early Hyp page allocator Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15 ` [RFC PATCH 11/27] KVM: arm64: Stub CONFIG_DEBUG_LIST at Hyp Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15 ` [RFC PATCH 12/27] KVM: arm64: Introduce a Hyp buddy page allocator Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15 ` [RFC PATCH 13/27] KVM: arm64: Enable access to sanitized CPU features at EL2 Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-23 10:55   ` Fuad Tabba
2020-11-23 10:55     ` Fuad Tabba
2020-11-23 10:55     ` Fuad Tabba
2020-11-23 13:51     ` Quentin Perret
2020-11-23 13:51       ` Quentin Perret
2020-11-23 13:51       ` Quentin Perret
2020-11-23 13:22   ` David Brazdil
2020-11-23 13:22     ` David Brazdil
2020-11-23 13:22     ` David Brazdil
2020-11-23 14:39     ` Quentin Perret
2020-11-23 14:39       ` Quentin Perret
2020-11-23 14:39       ` Quentin Perret
2020-11-17 18:15 ` [RFC PATCH 14/27] KVM: arm64: Factor out vector address calculation Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15 ` [RFC PATCH 15/27] of/fdt: Introduce early_init_dt_add_memory_hyp() Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 19:44   ` Rob Herring
2020-11-17 19:44     ` Rob Herring
2020-11-17 19:44     ` Rob Herring
2020-11-18  9:25     ` Quentin Perret
2020-11-18  9:25       ` Quentin Perret
2020-11-18  9:25       ` Quentin Perret
2020-11-18 14:31       ` Quentin Perret
2020-11-18 14:31         ` Quentin Perret
2020-11-18 14:31         ` Quentin Perret
2020-11-17 18:15 ` [RFC PATCH 16/27] KVM: arm64: Prepare Hyp memory protection Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-12-03 12:57   ` Fuad Tabba
2020-12-03 12:57     ` Fuad Tabba
2020-12-03 12:57     ` Fuad Tabba
2020-12-04 18:01     ` Quentin Perret
2020-12-04 18:01       ` Quentin Perret
2020-12-04 18:01       ` Quentin Perret
2020-12-07 10:20       ` Will Deacon [this message]
2020-12-07 10:20         ` Will Deacon
2020-12-07 10:20         ` Will Deacon
2020-12-07 11:05         ` Mark Rutland
2020-12-07 11:05           ` Mark Rutland
2020-12-07 11:05           ` Mark Rutland
2020-12-07 11:10           ` Will Deacon
2020-12-07 11:10             ` Will Deacon
2020-12-07 11:10             ` Will Deacon
2020-12-07 11:14           ` Fuad Tabba
2020-12-07 11:14             ` Fuad Tabba
2020-12-07 11:14             ` Fuad Tabba
2020-12-07 11:16       ` Fuad Tabba
2020-12-07 11:16         ` Fuad Tabba
2020-12-07 11:16         ` Fuad Tabba
2020-12-07 11:58         ` Quentin Perret
2020-12-07 11:58           ` Quentin Perret
2020-12-07 11:58           ` Quentin Perret
2020-12-07 13:54           ` Marc Zyngier
2020-12-07 13:54             ` Marc Zyngier
2020-12-07 13:54             ` Marc Zyngier
2020-12-07 14:17             ` Quentin Perret
2020-12-07 14:17               ` Quentin Perret
2020-12-07 14:17               ` Quentin Perret
2020-12-07 13:40   ` Will Deacon
2020-12-07 13:40     ` Will Deacon
2020-12-07 13:40     ` Will Deacon
2020-12-07 14:11     ` Quentin Perret
2020-12-07 14:11       ` Quentin Perret
2020-12-07 14:11       ` Quentin Perret
2020-12-08  9:40       ` Will Deacon
2020-12-08  9:40         ` Will Deacon
2020-12-08  9:40         ` Will Deacon
2020-11-17 18:15 ` [RFC PATCH 17/27] KVM: arm64: Elevate Hyp mappings creation at EL2 Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15 ` [RFC PATCH 18/27] KVM: arm64: Use kvm_arch for stage 2 pgtable Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15 ` [RFC PATCH 19/27] KVM: arm64: Use kvm_arch in kvm_s2_mmu Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:15   ` Quentin Perret
2020-11-17 18:16 ` [RFC PATCH 20/27] KVM: arm64: Set host stage 2 using kvm_nvhe_init_params Quentin Perret
2020-11-17 18:16   ` Quentin Perret
2020-11-17 18:16   ` Quentin Perret
2020-11-17 18:16 ` [RFC PATCH 21/27] KVM: arm64: Refactor kvm_arm_setup_stage2() Quentin Perret
2020-11-17 18:16   ` Quentin Perret
2020-11-17 18:16   ` Quentin Perret
2020-11-17 18:16 ` [RFC PATCH 22/27] KVM: arm64: Refactor __load_guest_stage2() Quentin Perret
2020-11-17 18:16   ` Quentin Perret
2020-11-17 18:16   ` Quentin Perret
2020-11-17 18:16 ` [RFC PATCH 23/27] KVM: arm64: Refactor __populate_fault_info() Quentin Perret
2020-11-17 18:16   ` Quentin Perret
2020-11-17 18:16   ` Quentin Perret
2020-11-17 18:16 ` [RFC PATCH 24/27] KVM: arm64: Make memcache anonymous in pgtable allocator Quentin Perret
2020-11-17 18:16   ` Quentin Perret
2020-11-17 18:16   ` Quentin Perret
2020-11-17 18:16 ` [RFC PATCH 25/27] KVM: arm64: Reserve memory for host stage 2 Quentin Perret
2020-11-17 18:16   ` Quentin Perret
2020-11-17 18:16   ` Quentin Perret
2020-11-17 18:16 ` [RFC PATCH 26/27] KVM: arm64: Sort the memblock regions list Quentin Perret
2020-11-17 18:16   ` Quentin Perret
2020-11-17 18:16   ` Quentin Perret
2020-11-17 18:16 ` [RFC PATCH 27/27] KVM: arm64: Wrap the host with a stage 2 Quentin Perret
2020-11-17 18:16   ` Quentin Perret
2020-11-17 18:16   ` Quentin Perret

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