From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 68BC83C1083 for ; Mon, 31 Aug 2026 22:44:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788216265; cv=none; b=SjCiT0T9Zq/Kr6z51wm39poGDBZvC6FJJSarkSyPASOrURChyyNGZSrxR/SnWrQfJH6sUhH+OklTHCreLCsXIa5k4jdgf9bl75noPqoli9dtCAes9lq6Nlap7svLTkET5LLYoHEmYtSBrykteQL6F51WR/eXd17aU0xtQk0BDZI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788216265; c=relaxed/simple; bh=/kR8qx04GaK1fozh91ZrueT9taUY09NoFMimXg43G9c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Itch56sdSDr8N3mHTC0ajj50/Tg4iQALtQmBLs1w01su23BoxsxseuezU7IqtishM8cENjt9yDfRBhwxmXl3fCEhc7gD5Q8saytihTZbl255DySOJF41jqWFr4pKRzegJC18MStZqBJXRsDOnenX+xO/3NqA4fHAzdWAKMQB858= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Zv6Wh5jz; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Zv6Wh5jz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8F5C01F00A3F; Mon, 31 Aug 2026 22:44:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788216264; bh=i/l3TsS26Qm2RgkOwjKSwq7WahiYxc5glvcqes89URg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Zv6Wh5jzPd5ZSL1/ukKpichHsVbMdiEzKe7D306hNpnKpjy4XPH/AvnxmrR5nFNRI BQx/UCD0/itOt40Ko2fACc1IjdAL+hW1HMpshG9yqy64tD+OePlFMWRzGIIcApx0t/ xfes3rK3c16di/MLEXnAL71RWaFc9/S+A6fRb01UkSDJ5ZOJRct693JZJiymIfWAV4 ejgQrLG4CuatfGWEJBX+X4jUT/EF/YFWpNQoC/tbuIOOsKaQNBqbV5Bu7qdUv7ovqT UjSzKR7fh5r2mR5ED5bMuPq3ZYmYrLnqUmSjXoPZq1pgJKNqnukkEauVlrwTs9C3yK HHnXi8ym54tlw== From: Sasha Levin To: stable@vger.kernel.org Cc: Sean Christopherson , Michael Roth , Sasha Levin Subject: [PATCH 7.1.y 6/8] KVM: x86/mmu: Split kvm_mmu_zap_all_fast() into "front" and "back" halves Date: Mon, 31 Aug 2026 18:44:15 -0400 Message-ID: <20260831224417.1903154-6-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260831224417.1903154-1-sashal@kernel.org> References: <2026083159-request-customs-f573@gregkh> <20260831224417.1903154-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Sean Christopherson [ Upstream commit b27622c4eeb125814081baaefe9175191be5b94d ] 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 Link: https://patch.msgid.link/20260709204948.1988414-9-seanjc@google.com Signed-off-by: Sean Christopherson Stable-dep-of: d1a3c2162334 ("KVM: SEV: Forcefully invalidate SNP VMSA if its backing gmem page is zapped") Signed-off-by: Sasha Levin --- 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 73358100e0018..10c28f78bf276 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -6802,20 +6802,11 @@ 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); /* @@ -6852,8 +6843,12 @@ 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 @@ -6867,6 +6862,24 @@ 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; -- 2.53.0