From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Ben Gardon <bgardon@google.com>
Subject: [PATCH 2/2] KVM: x86/mmu: Drop 'shared' param from tdp_mmu_link_page()
Date: Tue, 10 Aug 2021 15:45:54 -0700 [thread overview]
Message-ID: <20210810224554.2978735-3-seanjc@google.com> (raw)
In-Reply-To: <20210810224554.2978735-1-seanjc@google.com>
Drop @shared from tdp_mmu_link_page() and hardcode it to work for
mmu_lock being held for read. The helper has exactly one caller and
in all likelihood will only ever have exactly one caller. Even if KVM
adds a path to install translations without an initiating page fault,
odds are very, very good that the path will just be a wrapper to the
"page fault" handler (both SNP and TDX RFCs propose patches to do
exactly that).
No functional change intended.
Cc: Ben Gardon <bgardon@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/mmu/tdp_mmu.c | 17 ++++-------------
1 file changed, 4 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index d99e064d366f..c5b901744d15 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -257,26 +257,17 @@ static void handle_changed_spte_dirty_log(struct kvm *kvm, int as_id, gfn_t gfn,
*
* @kvm: kvm instance
* @sp: the new page
- * @shared: This operation may not be running under the exclusive use of
- * the MMU lock and the operation must synchronize with other
- * threads that might be adding or removing pages.
* @account_nx: This page replaces a NX large page and should be marked for
* eventual reclaim.
*/
static void tdp_mmu_link_page(struct kvm *kvm, struct kvm_mmu_page *sp,
- bool shared, bool account_nx)
+ bool account_nx)
{
- if (shared)
- spin_lock(&kvm->arch.tdp_mmu_pages_lock);
- else
- lockdep_assert_held_write(&kvm->mmu_lock);
-
+ spin_lock(&kvm->arch.tdp_mmu_pages_lock);
list_add(&sp->link, &kvm->arch.tdp_mmu_pages);
if (account_nx)
account_huge_nx_page(kvm, sp);
-
- if (shared)
- spin_unlock(&kvm->arch.tdp_mmu_pages_lock);
+ spin_unlock(&kvm->arch.tdp_mmu_pages_lock);
}
/**
@@ -1062,7 +1053,7 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
!shadow_accessed_mask);
if (tdp_mmu_set_spte_atomic_no_dirty_log(vcpu->kvm, &iter, new_spte)) {
- tdp_mmu_link_page(vcpu->kvm, sp, true,
+ tdp_mmu_link_page(vcpu->kvm, sp,
huge_page_disallowed &&
req_level >= iter.level);
--
2.32.0.605.g8dce9f2422-goog
next prev parent reply other threads:[~2021-08-10 22:46 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-10 22:45 [PATCH 0/2] KVM: x86/mmu: Fix unsync races within TDP MMU Sean Christopherson
2021-08-10 22:45 ` [PATCH 1/2] KVM: x86/mmu: Protect marking SPs unsync when using TDP MMU with spinlock Sean Christopherson
2021-08-11 11:47 ` Paolo Bonzini
2021-08-11 15:52 ` Sean Christopherson
2021-08-12 15:37 ` Paolo Bonzini
2021-08-12 16:06 ` Sean Christopherson
2021-08-10 22:45 ` Sean Christopherson [this message]
2021-08-11 16:33 ` [PATCH 2/2] KVM: x86/mmu: Drop 'shared' param from tdp_mmu_link_page() Ben Gardon
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210810224554.2978735-3-seanjc@google.com \
--to=seanjc@google.com \
--cc=bgardon@google.com \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=vkuznets@redhat.com \
--cc=wanpengli@tencent.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox