Re: [PATCH v13 12/35] KVM: Prepare for handling only shared mappings in mmu_notifier events

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]


On 10/28/2023 2:21 AM, Sean Christopherson wrote:
Add flags to "struct kvm_gfn_range" to let notifier events target only
shared and only private mappings, and write up the existing mmu_notifier
events to be shared-only (private memory is never associated with a
userspace virtual address, i.e. can't be reached via mmu_notifiers).

Add two flags so that KVM can handle the three possibilities (shared,
private, and shared+private) without needing something like a tri-state
I see the two flags are set/cleared in __kvm_handle_hva_range() in this patch
and kvm_handle_gfn_range() from the later patch 13/35, but I didn't see they
are used/read in this patch series if I didn't miss anything.  How are they
supposed to be used in KVM?

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
  include/linux/kvm_host.h | 2 ++
  virt/kvm/kvm_main.c      | 7 +++++++
  2 files changed, 9 insertions(+)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 96aa930536b1..89c1a991a3b8 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -263,6 +263,8 @@ struct kvm_gfn_range {
  	gfn_t start;
  	gfn_t end;
  	union kvm_mmu_notifier_arg arg;
+	bool only_private;
+	bool only_shared;
  	bool may_block;
  bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index cb9376833c18..302ccb87b4c1 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -635,6 +635,13 @@ static __always_inline kvm_mn_ret_t __kvm_handle_hva_range(struct kvm *kvm,
  			 * the second or later invocation of the handler).
  			gfn_range.arg = range->arg;
+			/*
+			 * HVA-based notifications aren't relevant to private
+			 * mappings as they don't have a userspace mapping.
+			 */
+			gfn_range.only_private = false;
+			gfn_range.only_shared = true;
  			gfn_range.may_block = range->may_block;

[Index of Archives]     [LKML Archive]     [Linux ARM Kernel]     [Linux ARM]     [Git]     [Yosemite News]     [Linux SCSI]     [Linux Hams]

  Powered by Linux