Re: [PATCH v3 07/15] KVM: arm64: Introduce kvm_share_hyp()
From: Will Deacon <will@kernel.org>
Date: 2021-12-09 11:13:22
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kvmarm, lkml
On Wed, Dec 01, 2021 at 05:04:01PM +0000, Quentin Perret wrote:
The create_hyp_mappings() function can currently be called at any point in time. However, its behaviour in protected mode changes widely depending on when it is being called. Prior to KVM init, it is used to create the temporary page-table used to bring-up the hypervisor, and later on it is transparently turned into a 'share' hypercall when the kernel has lost control over the hypervisor stage-1. In order to prepare the ground for also unsharing pages with the hypervisor during guest teardown, introduce a kvm_share_hyp() function to make it clear in which places a share hypercall should be expected, as we will soon need a matching unshare hypercall in all those places. Signed-off-by: Quentin Perret <redacted> --- arch/arm64/include/asm/kvm_mmu.h | 1 + arch/arm64/kvm/arm.c | 4 ++-- arch/arm64/kvm/fpsimd.c | 2 +- arch/arm64/kvm/mmu.c | 27 +++++++++++++++++++++------ arch/arm64/kvm/reset.c | 2 +- 5 files changed, 26 insertions(+), 10 deletions(-)
[...]
quoted hunk ↗ jump to hunk
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index f8f1096a297f..fd868fb9d922 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c@@ -299,6 +299,25 @@ static int pkvm_share_hyp(phys_addr_t start, phys_addr_t end) return 0; } +int kvm_share_hyp(void *from, void *to) +{ + if (is_kernel_in_hyp_mode()) + return 0; + + /* + * The share hcall maps things in the 'fixed-offset' region of the hyp + * VA space, so we can only share physically contiguous data-structures + * for now. + */ + if (is_vmalloc_addr(from) || is_vmalloc_addr(to)) + return -EINVAL;
If we're adding these sanity checks, perhaps is_vmalloc_or_module_addr() would be worth using instead? Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel