From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f202.google.com (mail-pf1-f202.google.com [209.85.210.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AF5A8330B01 for ; Tue, 30 Jun 2026 22:26:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782858384; cv=none; b=tJEMTcPowyvtdae8lFu44FIAP0aAVm/yN5nlY6pWHtNr7TqhcQTZZuVvH+wC3zbqkG3ezFOrjMvoQcgFYSvirqxc+pbQmorPzpx/HYRD5idlUMWlHvh5dJh3A65YCgJes8YC3qHQANZTE3Jhf/p/dk6tN527I35SwmULcbchVzM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782858384; c=relaxed/simple; bh=+5x/gZYgDX9Id5/FW01iE47gRpQ3ZoZYUlfRa6A5Bok=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Kr2cgOrBE9tHX3CPeHJMNx5Qi/mStr5AOLqUZTMcsiIcaxUvIEyf6fSHObPJEOh83tHq7S9jO1aKRgxOklutzBBdTQm2Em3+MhYHfnpLa5jj0nLD/4cCBl4sJ3rGjTRPcJp0xHCgvrN1Y8hpLgJIrRegwo50awG1ii7I5QxmRMY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=Xji/qy6a; arc=none smtp.client-ip=209.85.210.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Xji/qy6a" Received: by mail-pf1-f202.google.com with SMTP id d2e1a72fcca58-845df469a26so91295b3a.3 for ; Tue, 30 Jun 2026 15:26:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1782858378; x=1783463178; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=Otm9wLBQIuFX//qUFsPztN/wAvyyH1/6HpJNM8Zumtk=; b=Xji/qy6aSRftKgG/V9dbCpC5vY36SNKW8L38LOuwAxCnEI0MvQ2RDTlAKGf20PlUk7 EdrKgj0D3o9eMYFO4DyohPTh9/hAkjcMgaYJAunQY/VOJ6ifZsk8WogMKOnJ8wksEoFq aN71reUqj3WbW3QZg+TUNkOzYe62sgRJ9EuoxHmH4DacPjkWnPXL0+6GQTg5WEP9k1k/ d1OCjnZAf4KAHLvoS8QvakJLDjH86nAqaufjRghQS53SfclZCUv2bIr4PDA+RdowK4bb OrrY0mv5+65R0KPZXlFkYa4JhQ4m8CG0Rs4tIt5CVLxjWEq6vdLOMsNK2xftVpHxk/3d M3yw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782858378; x=1783463178; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=Otm9wLBQIuFX//qUFsPztN/wAvyyH1/6HpJNM8Zumtk=; b=l8EYRHyuVo6bSKYED4EralknAUTudEbRZWm5WIBHVucDr2IrHiQgvCV8EM8Wh5GBL7 TcgObBGrHLJ3J43yJ26GkZQ4Sv3bAlSw0N9mNsdbuTGlqgRK3ge43xs/e+Vj8HR0dyOq U3TL8d+Z4R+IO93IfbVHdnpAy9bzpkakPT+VBCqde1txzO6TRDDWf9WC8TDHVqmDA2qy 3cXj6mlQ0kvy3PNMjKwtk4QR5E86LCvPBw9Dx/6RD3VaZpJuXa1a3NTJx/vS/Y4fJx9Z 30daYWb1eakJpBziID9X8NuKdgIlB80aJJ0yOEiZJ4J30Pb3dEGfgSNgPegf2UEUCyT6 l0QA== X-Forwarded-Encrypted: i=1; AHgh+Rohj9NzFMxn1Ng7VVEpJfx8fZ7rD5RhuKNnmHkFqoyXLLT6a3Z17rptwHH2sexJ0Hzyzr3Qhe6b1Ny8BS8=@vger.kernel.org X-Gm-Message-State: AOJu0YxPrOJR+6NBKeyjzB9rmA9KmDbD2WjbiSZIJd2UlKGCbhCp8zVw G03xyXaCky+kSNZkcnyo8r0icQCeeEB5pBN1TO+AvIyHvRUogYUoA+TE3bDOVz+c9JlRkh0A3DW 44CBWdg== X-Received: from pfbbv13.prod.google.com ([2002:a05:6a00:414d:b0:847:82b3:aca]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:94c3:b0:847:77e7:6f64 with SMTP id d2e1a72fcca58-8479eef4456mr4502380b3a.20.1782858377707; Tue, 30 Jun 2026 15:26:17 -0700 (PDT) Reply-To: Sean Christopherson Date: Tue, 30 Jun 2026 15:26:03 -0700 In-Reply-To: <20260630222607.497895-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260630222607.497895-1-seanjc@google.com> X-Mailer: git-send-email 2.55.0.rc0.799.gd6f94ed593-goog Message-ID: <20260630222607.497895-9-seanjc@google.com> Subject: [PATCH v3 08/12] KVM: x86/mmu: Split kvm_mmu_zap_all_fast() into "front" and "back" halves From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Ackerley Tng , Hyunwoo Kim , Tom Lendacky , Michael Roth , "=?UTF-8?q?J=C3=B6rg=20R=C3=B6del?=" , Fuad Tabba Content-Type: text/plain; charset="UTF-8" Split kvm_mmu_zap_all_fast() into a "front half" and a "back half", where the front half is everything that runs with mmu_lock held for write, and the back half is the code that runs outside of mmu_lock. This will allow putting more code inside kvm_arch_flush_shadow_memslot()'s critical section without having to take mmu_lock twice in quick succession. No functional change intended. Cc: stable@vger.kernel.org # 6.12.x Signed-off-by: Sean Christopherson --- arch/x86/kvm/mmu/mmu.c | 37 +++++++++++++++++++++++++------------ 1 file changed, 25 insertions(+), 12 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 223d80b12b9b..a5c2a560a88a 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -6921,20 +6921,11 @@ static void kvm_zap_obsolete_pages(struct kvm *kvm) kvm_mmu_commit_zap_page(kvm, &invalid_list); } -/* - * Fast invalidate all shadow pages and use lock-break technique - * to zap obsolete pages. - * - * It's required when memslot is being deleted or VM is being - * destroyed, in these cases, we should ensure that KVM MMU does - * not use any resource of the being-deleted slot or all slots - * after calling the function. - */ -static void kvm_mmu_zap_all_fast(struct kvm *kvm) +static void __kvm_mmu_zap_all_fast_front_half(struct kvm *kvm) { lockdep_assert_held(&kvm->slots_lock); + lockdep_assert_held_write(&kvm->mmu_lock); - write_lock(&kvm->mmu_lock); trace_kvm_mmu_zap_all_fast(kvm); /* @@ -6971,8 +6962,12 @@ static void kvm_mmu_zap_all_fast(struct kvm *kvm) kvm_make_all_cpus_request(kvm, KVM_REQ_MMU_FREE_OBSOLETE_ROOTS); kvm_zap_obsolete_pages(kvm); +} - write_unlock(&kvm->mmu_lock); +static void __kvm_mmu_zap_all_fast_back_half(struct kvm *kvm) +{ + lockdep_assert_held(&kvm->slots_lock); + lockdep_assert_not_held(&kvm->mmu_lock); /* * Zap the invalidated TDP MMU roots, all SPTEs must be dropped before @@ -6986,6 +6981,24 @@ static void kvm_mmu_zap_all_fast(struct kvm *kvm) kvm_tdp_mmu_zap_invalidated_roots(kvm, true); } +/* + * Fast invalidate all shadow pages and use lock-break technique + * to zap obsolete pages. + * + * It's required when memslot is being deleted or VM is being + * destroyed, in these cases, we should ensure that KVM MMU does + * not use any resource of the being-deleted slot or all slots + * after calling the function. + */ +static void kvm_mmu_zap_all_fast(struct kvm *kvm) +{ + write_lock(&kvm->mmu_lock); + __kvm_mmu_zap_all_fast_front_half(kvm); + write_unlock(&kvm->mmu_lock); + + __kvm_mmu_zap_all_fast_back_half(kvm); +} + int kvm_mmu_init_vm(struct kvm *kvm) { int r, i; -- 2.55.0.rc0.799.gd6f94ed593-goog