Re: [PATCH v10 9/9] KVM: Enable and expose KVM_MEM_PRIVATE
From: Chao Peng <hidden>
Date: 2023-01-28 14:09:10
Also in:
kvm, linux-arch, linux-doc, linux-fsdevel, linux-mm, lkml, qemu-devel
Subsystem:
kernel virtual machine (kvm), the rest · Maintainers:
Paolo Bonzini, Linus Torvalds
On Sat, Jan 14, 2023 at 12:01:01AM +0000, Sean Christopherson wrote:
On Fri, Dec 02, 2022, Chao Peng wrote:
...
Strongly prefer to use similar logic to existing code that detects wraps: mem->restricted_offset + mem->memory_size < mem->restricted_offset This is also where I'd like to add the "gfn is aligned to offset" check, though my brain is too fried to figure that out right now.
Used count_trailing_zeros() for this TODO, unsure we have other better approach.
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index afc8c26fa652..fd34c5f7cd2f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c@@ -56,6 +56,7 @@ #include <asm/processor.h> #include <asm/ioctl.h> #include <linux/uaccess.h> +#include <linux/count_zeros.h> #include "coalesced_mmio.h" #include "async_pf.h"
@@ -2087,6 +2088,19 @@ static bool kvm_check_memslot_overlap(struct kvm_memslots *slots, int id, return false; } +/* + * Return true when ALIGNMENT(offset) >= ALIGNMENT(gpa). + */ +static bool kvm_check_rmem_offset_alignment(u64 offset, u64 gpa) +{ + if (!offset) + return true; + if (!gpa) + return false; + + return !!(count_trailing_zeros(offset) >= count_trailing_zeros(gpa)); +} + /* * Allocate some memory and give it an address in the guest physical address * space.
@@ -2128,7 +2142,8 @@ int __kvm_set_memory_region(struct kvm *kvm, if (mem->flags & KVM_MEM_PRIVATE && (mem->restrictedmem_offset & (PAGE_SIZE - 1) || mem->restrictedmem_offset + mem->memory_size < mem->restrictedmem_offset || - 0 /* TODO: require gfn be aligned with restricted offset */)) + !kvm_check_rmem_offset_alignment(mem->restrictedmem_offset, + mem->guest_phys_addr))) return -EINVAL; if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_MEM_SLOTS_NUM) return -EINVAL;