Re: [RFC PATCH v2 00/26] KVM/arm64: A stage 2 for the host
On Fri, Jan 08, 2021, Quentin Perret wrote: > [2] > https://kvmforum2020.sched.com/event/eE24/virtualization-for-the-masses-exposing-kvm-on-android-will-deacon-google I couldn't find any slides on the official KVM forum site linked above. I was able to track down a mirror[1] and the recorded presentation[2]. [1] https://mirrors.edge.kernel.org/pub/linux/kernel/people/will/slides/kvmforum-2020-edited.pdf [2] https://youtu.be/wY-u6n75iXc ___ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
Re: [RFC PATCH v2 00/26] KVM/arm64: A stage 2 for the host
On Friday 19 Feb 2021 at 09:54:38 (-0800), Sean Christopherson wrote: > On Fri, Jan 08, 2021, Quentin Perret wrote: > > [2] > > https://kvmforum2020.sched.com/event/eE24/virtualization-for-the-masses-exposing-kvm-on-android-will-deacon-google > > I couldn't find any slides on the official KVM forum site linked above. I was > able to track down a mirror[1] and the recorded presentation[2]. > > [1] > https://mirrors.edge.kernel.org/pub/linux/kernel/people/will/slides/kvmforum-2020-edited.pdf > [2] https://youtu.be/wY-u6n75iXc Much nicer, I'll make sure to link those in the next cover letter. Thanks Sean! Quentin ___ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
Re: [RFC PATCH v2 00/26] KVM/arm64: A stage 2 for the host
Hi Mate, On Wednesday 17 Feb 2021 at 17:27:07 (+0100), Mate Toth-Pal wrote: > We tested the pKVM changes pulled from here: > > > > https://android-kvm.googlesource.com/linux qperret/host-stage2-v2 > > > We were using a target with Arm architecture with FEAT_S2FWB, and found that > there is a bug in the patch. > > > It turned out that the Kernel checks for the extension, and sets up the > stage 2 translation so that it forces the host memory type to write-through. > However it seems that the code doesn't turn on the feature in the HCR_EL2 > register. > > > We were able to fix the issue by applying the following patch: > > > diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c > b/arch/arm64/kvm/hyp/nvhe/mem_protect.c > index 0cd3eb178f3b..e8521a072ea6 100644 > --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c > +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c > @@ -105,6 +105,8 @@ int kvm_host_prepare_stage2(void *mem_pgt_pool, void > *dev_pgt_pool) > params->vttbr = kvm_get_vttbr(mmu); > params->vtcr = host_kvm.arch.vtcr; > params->hcr_el2 |= HCR_VM; > + if (cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) > + params->hcr_el2 |= HCR_FWB; > __flush_dcache_area(params, sizeof(*params)); > } Aha, indeed, this looks right. I'll double check HCR_EL2 to see if I'm missing any other, and I'll add this to v3. Thanks for testing, and the for the report. Quentin ___ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
Re: [RFC PATCH v2 00/26] KVM/arm64: A stage 2 for the host
Hi Quentin, On 2021-01-08 13:14, Quentin Perret wrote: Hi all, This is the v2 of the series previously posted here: https://lore.kernel.org/kvmarm/20201117181607.1761516-1-qper...@google.com/ This basically allows us to wrap the host with a stage 2 when running in nVHE, hence paving the way for protecting guest memory from the host in the future (among other use-cases). For more details about the motivation and the design angle taken here, I would recommend to have a look at the cover letter of v1, and/or to watch these presentations at LPC [1] and KVM forum 2020 [2]. We tested the pKVM changes pulled from here: https://android-kvm.googlesource.com/linux qperret/host-stage2-v2 We were using a target with Arm architecture with FEAT_S2FWB, and found that there is a bug in the patch. It turned out that the Kernel checks for the extension, and sets up the stage 2 translation so that it forces the host memory type to write-through. However it seems that the code doesn't turn on the feature in the HCR_EL2 register. We were able to fix the issue by applying the following patch: diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index 0cd3eb178f3b..e8521a072ea6 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -105,6 +105,8 @@ int kvm_host_prepare_stage2(void *mem_pgt_pool, void *dev_pgt_pool) params->vttbr = kvm_get_vttbr(mmu); params->vtcr = host_kvm.arch.vtcr; params->hcr_el2 |= HCR_VM; + if (cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) + params->hcr_el2 |= HCR_FWB; __flush_dcache_area(params, sizeof(*params)); } Best regards, Mate Toth-Pal ___ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
[RFC PATCH v2 00/26] KVM/arm64: A stage 2 for the host
Hi all,
This is the v2 of the series previously posted here:
https://lore.kernel.org/kvmarm/20201117181607.1761516-1-qper...@google.com/
This basically allows us to wrap the host with a stage 2 when running in
nVHE, hence paving the way for protecting guest memory from the host in
the future (among other use-cases). For more details about the
motivation and the design angle taken here, I would recommend to have a
look at the cover letter of v1, and/or to watch these presentations at
LPC [1] and KVM forum 2020 [2].
In short, the changes since v1 include:
- Renamed most pkvm-specific pgtable functions as pkvm_* to avoid
confusion with the host's (Fuad)
- Added an IC flush when switching pgtables (Fuad, Mark)
- Cleaned-up the PI aliasing in image-vars.h (David)
- Added a TLB flush when enabling the host stage 2 to avoid stale TLBs
from bootloader
- Fixed the early memory reservation by using NR_CPUS instead of
num_possible_cpus() (which is always 1 that early)
- Added missing preempt_{dis,en}able() guards in
kvm_hyp_enable_protection()
- Rebased on latest kvmarm/next
And if you'd like a branch that has all the goodies, there it is:
https://android-kvm.googlesource.com/linux qperret/host-stage2-v2
Thanks!
Quentin
[1] https://youtu.be/54q6RzS9BpQ?t=10859
[2]
https://kvmforum2020.sched.com/event/eE24/virtualization-for-the-masses-exposing-kvm-on-android-will-deacon-google
Quentin Perret (23):
KVM: arm64: Initialize kvm_nvhe_init_params early
KVM: arm64: Avoid free_page() in page-table allocator
KVM: arm64: Factor memory allocation out of pgtable.c
KVM: arm64: Introduce a BSS section for use at Hyp
KVM: arm64: Make kvm_call_hyp() a function call at Hyp
KVM: arm64: Allow using kvm_nvhe_sym() in hyp code
KVM: arm64: Introduce an early Hyp page allocator
KVM: arm64: Stub CONFIG_DEBUG_LIST at Hyp
KVM: arm64: Introduce a Hyp buddy page allocator
KVM: arm64: Enable access to sanitized CPU features at EL2
KVM: arm64: Factor out vector address calculation
of/fdt: Introduce early_init_dt_add_memory_hyp()
KVM: arm64: Prepare Hyp memory protection
KVM: arm64: Elevate Hyp mappings creation at EL2
KVM: arm64: Use kvm_arch for stage 2 pgtable
KVM: arm64: Use kvm_arch in kvm_s2_mmu
KVM: arm64: Set host stage 2 using kvm_nvhe_init_params
KVM: arm64: Refactor kvm_arm_setup_stage2()
KVM: arm64: Refactor __load_guest_stage2()
KVM: arm64: Refactor __populate_fault_info()
KVM: arm64: Make memcache anonymous in pgtable allocator
KVM: arm64: Reserve memory for host stage 2
KVM: arm64: Wrap the host with a stage 2
Will Deacon (3):
arm64: lib: Annotate {clear,copy}_page() as position-independent
KVM: arm64: Link position-independent string routines into .hyp.text
arm64: kvm: Add standalone ticket spinlock implementation for use at
hyp
arch/arm64/include/asm/cpufeature.h | 1 +
arch/arm64/include/asm/hyp_image.h| 7 +
arch/arm64/include/asm/kvm_asm.h | 7 +
arch/arm64/include/asm/kvm_cpufeature.h | 19 ++
arch/arm64/include/asm/kvm_host.h | 16 +-
arch/arm64/include/asm/kvm_hyp.h | 8 +
arch/arm64/include/asm/kvm_mmu.h | 69 +-
arch/arm64/include/asm/kvm_pgtable.h | 41 +++-
arch/arm64/include/asm/sections.h | 1 +
arch/arm64/kernel/asm-offsets.c | 3 +
arch/arm64/kernel/cpufeature.c| 12 +
arch/arm64/kernel/image-vars.h| 33 +++
arch/arm64/kernel/vmlinux.lds.S | 7 +
arch/arm64/kvm/arm.c | 144 ++--
arch/arm64/kvm/hyp/Makefile | 2 +-
arch/arm64/kvm/hyp/include/hyp/switch.h | 36 +--
arch/arm64/kvm/hyp/include/nvhe/early_alloc.h | 14 ++
arch/arm64/kvm/hyp/include/nvhe/gfp.h | 32 +++
arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 33 +++
arch/arm64/kvm/hyp/include/nvhe/memory.h | 55 +
arch/arm64/kvm/hyp/include/nvhe/mm.h | 107 +
arch/arm64/kvm/hyp/include/nvhe/spinlock.h| 92
arch/arm64/kvm/hyp/nvhe/Makefile | 9 +-
arch/arm64/kvm/hyp/nvhe/cache.S | 13 ++
arch/arm64/kvm/hyp/nvhe/cpufeature.c | 8 +
arch/arm64/kvm/hyp/nvhe/early_alloc.c | 60 +
arch/arm64/kvm/hyp/nvhe/hyp-init.S| 41
arch/arm64/kvm/hyp/nvhe/hyp-main.c| 48
arch/arm64/kvm/hyp/nvhe/hyp.lds.S | 1 +
arch/arm64/kvm/hyp/nvhe/mem_protect.c | 191
arch/arm64/kvm/hyp/nvhe/mm.c | 174 ++
arch/arm64/kvm/hyp/nvhe/page_alloc.c | 185 +++
arch/arm64/kvm/hyp/nvhe/psci-relay.c | 4 +-
arch/arm64/kvm/hyp/nvhe/setup.c | 214 ++
arch/arm64/kvm/hyp/nvhe/stub.c| 22 ++
arch/arm64/kvm/hyp/nvhe/switch.c | 12 +-
arch/arm64/kvm/hyp/nvhe/tlb.c
