From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f201.google.com (mail-pl1-f201.google.com [209.85.214.201]) (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 5554F3E835F for ; Thu, 9 Jul 2026 20:50:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783630201; cv=none; b=KTKRHRF+5HN1ig3JeEAY0dhYXxm+OHJETf6wDmEb6vBZ+hANRwSmaWvI/DowsV8FY947/7isPOFtjhc6oA0jBCzuXhrV7ga06Eq/72WF7x7pYCZA7CGP3Bm4P5I49U5gyLXYf0UUsbiZP78sYYER5AtPHrIoJ89JByBSiKPbPQg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783630201; c=relaxed/simple; bh=WaZJ7P0SHOolS0ZYzuBxtL7zgUXLJrMDeC09btwdKto=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=cpcvAYhbb/BN/7+gTDG56t0ntXS99c86JfD4kk632whKsskvGtbt6WH/M19UsBblZfUfJ4BklEIhA5LSfIXiBEUPbqxbcUAlGpnj2mGM5dFZRx2ubkRBXDGx6dvBGrCj8W6eZ6MzZ0RAYLiHAKMBNPWtgCxV0UqiIplWcHnDCG8= 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=uDJt+mmS; arc=none smtp.client-ip=209.85.214.201 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="uDJt+mmS" Received: by mail-pl1-f201.google.com with SMTP id d9443c01a7336-2cc7e86e7c5so3536265ad.3 for ; Thu, 09 Jul 2026 13:50:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1783630200; x=1784235000; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:reply-to:from:to:cc:subject:date:message-id :reply-to:content-type; bh=bdJmrm0DM0tqLrnWsA7Ix9+cw5cKAYmoXa3Fe29H+DM=; b=uDJt+mmSM5HU0/5Y+SxlYISeRwBIJdg+joYkrbD5rfgTNrSLavwjr4Fu5X/eQsSLqM VMlJbXtL0swcKgke/5TqEtZofjwZGde+jkPHWQlP6yxf90pgN1U/UdlBPnV/9IzDqe5G 6V1avxU8NetLioylrQRWWHabPyLEpqqKHClSANwqYX20T7+UAJbX/SJHokMCH1bEFW7v 8BnsmdaS9shYsRMxK1aXfjhiHGN8VgO91H2Aud3/f6azh8d5NIAzvIO89gpr+riRoP/y caRJmjC2pcYjMA1TmaXNGc7pIE9QyktuQWXAKUpNiTRZSCACgV+stYb7tJNi8iNpX/57 hdYw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1783630200; x=1784235000; h=content-type: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:content-type; bh=bdJmrm0DM0tqLrnWsA7Ix9+cw5cKAYmoXa3Fe29H+DM=; b=Eqm8ngTYMGr2je+s3t1AjJQz939eIcQ6w8Q3fAHmMmPipsahi+LJ+FvgRsCQIcptSh BPWh79g15GtY/RdPJuNNbo/Dj0R/NN8KGOOG/V7/fwDt/IV/SAxu8fUR4EBDnFKszIA+ eBIo7Gqa90c/xgRo8PLqSo1V+suBt/Ku8VfsSqwZYW+vzjwFfnA+F8eSFey/OlUT83Dg i8aS3B8/WhT5st1Sxg5K8oqKr2c2zdg3GZQuQhtFuveqie2Rigjn6BWuN61hi7ZvoT+N z8koTi/PVOy+E8STjphOpe4j+i2OyBBr3tWi0L1grcwbI1Kafk6ln/YMU8urEE65hz4S lohg== X-Gm-Message-State: AOJu0YwEQJgOfUG53QQoWVH2veg8gfAotZRHJAQAuzzaDPOxvZZbFe8E 9oDY5daiglAZvscHhGN0u2xIqnkbEYpP6HAl6vpi00ohcxE3QHsQi/aE8O2pSyZzBuebUh2FyNr jL8gBVw== X-Received: from plps17.prod.google.com ([2002:a17:902:9891:b0:2cc:2c68:b71b]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:4b48:b0:2c2:be43:39bc with SMTP id d9443c01a7336-2ccea42ee1cmr85833005ad.22.1783630199534; Thu, 09 Jul 2026 13:49:59 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 9 Jul 2026 13:49:38 -0700 In-Reply-To: <20260709204948.1988414-1-seanjc@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260709204948.1988414-1-seanjc@google.com> X-Mailer: git-send-email 2.55.0.795.g602f6c329a-goog Message-ID: <20260709204948.1988414-9-seanjc@google.com> Subject: [PATCH v4 08/18] 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, Michael Roth , Hyunwoo Kim , Tom Lendacky , "=?UTF-8?q?J=C3=B6rg=20R=C3=B6del?=" , Fuad Tabba , Ackerley Tng 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 Reviewed-by: Michael Roth 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; -- 2.55.0.795.g602f6c329a-goog