commit f922c13e77 ("KVM: arm64: Introduce
pkvm_alloc_private_va_range()") and commit 92abe0f81e ("KVM: arm64:
Introduce hyp_alloc_private_va_range()") added an alignment for the
start address of any allocation into the nVHE hypervisor private VA
range.
This alignment (order of the size of the allocation) intends to enable
efficient stack verification (if the PAGE_SHIFT bit is zero, the stack
pointer is on the guard page and a stack overflow occurred).
But this is only necessary for stack allocation and can waste a lot of
VA space. So instead make stack-specific functions, handling the guard
page requirements, while other users (e.g. fixmap) will only get page
alignment.
Reviewed-by: Kalesh Singh <kaleshsingh@google.com>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230811112037.1147863-1-vdonnefort@google.com
* kvm-arm64/pkvm-vcpu-state: (25 commits)
: .
: Large drop of pKVM patches from Will Deacon and co, adding
: a private vm/vcpu state at EL2, managed independently from
: the EL1 state. From the cover letter:
:
: "This is version six of the pKVM EL2 state series, extending the pKVM
: hypervisor code so that it can dynamically instantiate and manage VM
: data structures without the host being able to access them directly.
: These structures consist of a hyp VM, a set of hyp vCPUs and the stage-2
: page-table for the MMU. The pages used to hold the hypervisor structures
: are returned to the host when the VM is destroyed."
: .
KVM: arm64: Use the pKVM hyp vCPU structure in handle___kvm_vcpu_run()
KVM: arm64: Don't unnecessarily map host kernel sections at EL2
KVM: arm64: Explicitly map 'kvm_vgic_global_state' at EL2
KVM: arm64: Maintain a copy of 'kvm_arm_vmid_bits' at EL2
KVM: arm64: Unmap 'kvm_arm_hyp_percpu_base' from the host
KVM: arm64: Return guest memory from EL2 via dedicated teardown memcache
KVM: arm64: Instantiate guest stage-2 page-tables at EL2
KVM: arm64: Consolidate stage-2 initialisation into a single function
KVM: arm64: Add generic hyp_memcache helpers
KVM: arm64: Provide I-cache invalidation by virtual address at EL2
KVM: arm64: Initialise hypervisor copies of host symbols unconditionally
KVM: arm64: Add per-cpu fixmap infrastructure at EL2
KVM: arm64: Instantiate pKVM hypervisor VM and vCPU structures from EL1
KVM: arm64: Add infrastructure to create and track pKVM instances at EL2
KVM: arm64: Rename 'host_kvm' to 'host_mmu'
KVM: arm64: Add hyp_spinlock_t static initializer
KVM: arm64: Include asm/kvm_mmu.h in nvhe/mem_protect.h
KVM: arm64: Add helpers to pin memory shared with the hypervisor at EL2
KVM: arm64: Prevent the donation of no-map pages
KVM: arm64: Implement do_donate() helper for donating memory
...
Signed-off-by: Marc Zyngier <maz@kernel.org>
The host at EL1 and the pKVM hypervisor at EL2 will soon need to
exchange memory pages dynamically for creating and destroying VM state.
Indeed, the hypervisor will rely on the host to donate memory pages it
can use to create guest stage-2 page-tables and to store VM and vCPU
metadata. In order to ease this process, introduce a
'struct hyp_memcache' which is essentially a linked list of available
pages, indexed by physical addresses so that it can be passed
meaningfully between the different virtual address spaces configured at
EL1 and EL2.
Tested-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221110190259.26861-18-will@kernel.org
Mapping pages in a guest page-table from within the pKVM hypervisor at
EL2 may require cache maintenance to ensure that the initialised page
contents is visible even to non-cacheable (e.g. MMU-off) accesses from
the guest.
In preparation for performing this maintenance at EL2, introduce a
per-vCPU fixmap which allows the pKVM hypervisor to map guest pages
temporarily into its stage-1 page-table for the purposes of cache
maintenance and, in future, poisoning on the reclaim path. The use of a
fixmap avoids the need for memory allocation or locking on the map()
path.
Tested-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Co-developed-by: Will Deacon <will@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221110190259.26861-15-will@kernel.org
The EL2 'vmemmap' array in nVHE Protected mode is currently very sparse:
only memory pages owned by the hypervisor itself have a matching 'struct
hyp_page'. However, as the size of this struct has been reduced
significantly since its introduction, it appears that we can now afford
to back the vmemmap for all of memory.
Having an easily accessible 'struct hyp_page' for every physical page in
memory provides the hypervisor with a simple mechanism to store metadata
(e.g. a refcount) that wouldn't otherwise fit in the very limited number
of software bits available in the host stage-2 page-table entries. This
will be used in subsequent patches when pinning host memory pages for
use by the hypervisor at EL2.
Tested-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221110190259.26861-4-will@kernel.org
pkvm_hyp_alloc_private_va_range() can be used to reserve private VA ranges
in the pKVM nVHE hypervisor. Allocations are aligned based on the order of
the requested size.
This will be used to implement stack guard pages for pKVM nVHE hypervisor
(in a subsequent patch in the series).
Credits to Quentin Perret <qperret@google.com> for the idea of moving
private VA allocation out of __pkvm_create_private_mapping()
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220420214317.3303360-3-kaleshsingh@google.com
CPUs vulnerable to Spectre-BHB either need to make an SMC-CC firmware
call from the vectors, or run a sequence of branches. This gets added
to the hyp vectors. If there is no support for arch-workaround-1 in
firmware, the indirect vector will be used.
kvm_init_vector_slots() only initialises the two indirect slots if
the platform is vulnerable to Spectre-v3a. pKVM's hyp_map_vectors()
only initialises __hyp_bp_vect_base if the platform is vulnerable to
Spectre-v3a.
As there are about to more users of the indirect vectors, ensure
their entries in hyp_spectre_vector_selector[] are always initialised,
and __hyp_bp_vect_base defaults to the regular VA mapping.
The Spectre-v3a check is moved to a helper
kvm_system_needs_idmapped_vectors(), and merged with the code
that creates the hyp mappings.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
* kvm-arm64/pkvm-cleanups-5.17:
: .
: pKVM cleanups from Quentin Perret:
:
: This series is a collection of various fixes and cleanups for KVM/arm64
: when running in nVHE protected mode. The first two patches are real
: fixes/improvements, the following two are minor cleanups, and the last
: two help satisfy my paranoia so they're certainly optional.
: .
KVM: arm64: pkvm: Make kvm_host_owns_hyp_mappings() robust to VHE
KVM: arm64: pkvm: Stub io map functions
KVM: arm64: Make __io_map_base static
KVM: arm64: Make the hyp memory pool static
KVM: arm64: pkvm: Disable GICv2 support
KVM: arm64: pkvm: Fix hyp_pool max order
Signed-off-by: Marc Zyngier <maz@kernel.org>
The __io_map_base variable is used at EL2 to track the end of the
hypervisor's "private" VA range in nVHE protected mode. However it
doesn't need to be used outside of mm.c, so let's make it static to keep
all the hyp VA allocation logic in one place.
Signed-off-by: Quentin Perret <qperret@google.com>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211208152300.2478542-5-qperret@google.com
kvm/hyp/reserved_mem.c contains host code executing at EL1 and is not
linked into the hypervisor object. Move the file into kvm/pkvm.c and
rework the headers so that the definitions shared between the host and
the hypervisor live in asm/kvm_pkvm.h.
Signed-off-by: Will Deacon <will@kernel.org>
Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211202171048.26924-4-will@kernel.org
The __pkvm_create_mappings() function is no longer used outside of
nvhe/mm.c, make it static.
Signed-off-by: Quentin Perret <qperret@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210809152448.1810400-22-qperret@google.com
Refactor the hypervisor stage-1 locking in nVHE protected mode to expose
a new pkvm_create_mappings_locked() function. This will be used in later
patches to allow walking and changing the hypervisor stage-1 without
releasing the lock.
Signed-off-by: Quentin Perret <qperret@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210809152448.1810400-20-qperret@google.com
When memory protection is enabled, the EL2 code needs the ability to
create and manage its own page-table. To do so, introduce a new set of
hypercalls to bootstrap a memory management system at EL2.
This leads to the following boot flow in nVHE Protected mode:
1. the host allocates memory for the hypervisor very early on, using
the memblock API;
2. the host creates a set of stage 1 page-table for EL2, installs the
EL2 vectors, and issues the __pkvm_init hypercall;
3. during __pkvm_init, the hypervisor re-creates its stage 1 page-table
and stores it in the memory pool provided by the host;
4. the hypervisor then extends its stage 1 mappings to include a
vmemmap in the EL2 VA space, hence allowing to use the buddy
allocator introduced in a previous patch;
5. the hypervisor jumps back in the idmap page, switches from the
host-provided page-table to the new one, and wraps up its
initialization by enabling the new allocator, before returning to
the host.
6. the host can free the now unused page-table created for EL2, and
will now need to issue hypercalls to make changes to the EL2 stage 1
mappings instead of modifying them directly.
Note that for the sake of simplifying the review, this patch focuses on
the hypervisor side of things. In other words, this only implements the
new hypercalls, but does not make use of them from the host yet. The
host-side changes will follow in a subsequent patch.
Credits to Will for __pkvm_init_switch_pgd.
Acked-by: Will Deacon <will@kernel.org>
Co-authored-by: Will Deacon <will@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210319100146.1149909-18-qperret@google.com
