Re: [PATCH v3 32/32] KVM: arm64: Protect the .hyp sections from the host
From: Will Deacon <will@kernel.org>
Date: 2021-03-05 19:14:32
Also in:
kvmarm, lkml
On Tue, Mar 02, 2021 at 03:00:02PM +0000, Quentin Perret wrote:
When KVM runs in nVHE protected mode, use the host stage 2 to unmap the hypervisor sections. The long-term goal is to ensure the EL2 code can remain robust regardless of the host's state, so this starts by making sure the host cannot e.g. write to the .hyp sections directly. Signed-off-by: Quentin Perret <redacted> --- arch/arm64/include/asm/kvm_asm.h | 1 + arch/arm64/kvm/arm.c | 46 +++++++++++++++++++ arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 2 + arch/arm64/kvm/hyp/nvhe/hyp-main.c | 9 ++++ arch/arm64/kvm/hyp/nvhe/mem_protect.c | 22 +++++++++ 5 files changed, 80 insertions(+)
[...]
quoted hunk ↗ jump to hunk
static void handle_host_hcall(struct kvm_cpu_context *host_ctxt)diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index 2252ad1a8945..ed480facdc88 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c@@ -196,6 +196,28 @@ static int host_stage2_idmap(u64 addr) return ret; } +int __pkvm_host_unmap(phys_addr_t start, phys_addr_t end) +{ + struct kvm_mem_range r1, r2; + int ret; + + /* + * host_stage2_unmap_dev_all() currently relies on MMIO mappings being + * non-persistent, so don't allow PROT_NONE in MMIO range. + */ + if (!find_mem_range(start, &r1) || !find_mem_range(end, &r2)) + return -EINVAL; + if (r1.start != r2.start) + return -EINVAL;
Feels like this should be in a helper to determine whether or not a range is solely covered by memory. Either way: Acked-by: Will Deacon <will@kernel.org> Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel