From nobody Fri Oct 3 15:31:33 2025 Received: from mail-pf1-f201.google.com (mail-pf1-f201.google.com [209.85.210.201]) (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 49B2025C6FF for ; Fri, 29 Aug 2025 00:06:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756426015; cv=none; b=P3Vw6HC3uPA9+L83AWvnJbZxlvSDQ29al/KS8ke7ylSEY4KzVcnMvXS3niZEgaC74DPDtglC7bdWVEBv9C97f8ka8rOkAY8fhfLSM/N6oGR7z/EK6ji2E2yzxRsQYW2G5U8nqkxsQWa+BvhdCeLqaJhZog13eedFDBVWPVwq2XA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756426015; c=relaxed/simple; bh=f7lHMZ8qJpaqmwv29QAX2RMeTqQVMVNV4EYMHS+5iLo=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=LqBck1p7KBy+vkzUAR73PYRnWNnsqEx8H5w6KHrT7nkp0R0zCXsPRuM8qhsVOcIs5nhKPfgnHLLSJqxQMsbeXv2U29bb1wgNMEDlN3cRJqCwxmpUBmFyhCm4ui6hnFiVxnsUs76q+0Y+OT5R7tWuClkmnbLSc3l0loPiZMpmQkg= 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=iN8DUsPd; arc=none smtp.client-ip=209.85.210.201 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="iN8DUsPd" Received: by mail-pf1-f201.google.com with SMTP id d2e1a72fcca58-76e2ea9366aso1372795b3a.2 for ; Thu, 28 Aug 2025 17:06:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1756426012; x=1757030812; 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=UOslP8m3lu4+oiJ697IMjpcaNHz3/4VIfEbOPXSKr7o=; b=iN8DUsPdbZ7mO3yl/EoO210QIlp3eCEDZVo+jYSUjCDvzYiR3vQ+K/L3qmOyCfekQc EeUXISMgucH7kaP17ZFLcPX79k5MU9v6WOqwEPtSadJrqiX4fA3gW661pH9VVCBWw7HC PdNMf2A0uRP1F5Dyg7bgUQXaPygeOuqmxV9PvRkO5psPw849MzQV/iP2MAy6lx/9uBOV sF0FNIkWtxPWdapOdSEZiwXuv/fmGDAP15tvgvhFbph4hqTllrcF9LH+aqfBBcOBvPR+ gqF5/ekHYQU1+CLbSK0H9H/jlubfFhy0nd2/taG792kyPauNQMDXyknqDOmuMIybZ/9q T3Iw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1756426012; x=1757030812; 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=UOslP8m3lu4+oiJ697IMjpcaNHz3/4VIfEbOPXSKr7o=; b=m3YuDHlC3psvwrIN393qBVCju3yPjBLXCCVy6ztFW3HxXx+H6OuYnDJOUvX7kxY5uf gGLafKp1bjIYMrsezcQDi64434heM5IQuThrrkao5goZ3mkNTwqP+RWxim7xCFwwRLZb 15Tk0xOzSbrSa2hCck3dDj+3tknHx+5z80QimX57jcfqsM+WnPOGhXAAM38vTM2jRvrQ O712s8yr6tPv+W+mektuRA38bSaYq5q/ANLtY0SE0nUbcJhjlruYjFR+h/DdWV93FiO8 uxgb+ArPaW0JWZeJCuTR7wg/O5D/cUIdL5JYj1NZns3PZewfqrbZbxUMpp20rxooIOiW jkZA== X-Forwarded-Encrypted: i=1; AJvYcCWxLRhLhYURu6zbRgIahpa16Bx3VWUTSNQbfsFbdWz5B2dD3Y0xHuXThLY27Z66nueNJkVKLDyUoVik5vg=@vger.kernel.org X-Gm-Message-State: AOJu0Yz1JZCiMkrt8MBiDzrYuVpEGmZofOF2nJFx6TdStaOLkvXzn6wc Y+fSpe65ipHgWfDgr+zznx1QEP+NsF4tvaCSe1mutBupM+D02E1aiSkiujqrHhMD01a2r/7w+Nn 4CYXDaQ== X-Google-Smtp-Source: AGHT+IGzyu2K+Q3S0JyMe3DS6644rOW4vURK+W47x0/xR9XONWf8AM78cfPpCJTbVijPrA+3JwtyO448ezo= X-Received: from pfbhg23.prod.google.com ([2002:a05:6a00:8617:b0:76e:313a:6f90]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:181e:b0:772:921:e32b with SMTP id d2e1a72fcca58-77209220d75mr10908984b3a.25.1756426012474; Thu, 28 Aug 2025 17:06:52 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 28 Aug 2025 17:06:18 -0700 In-Reply-To: <20250829000618.351013-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250829000618.351013-1-seanjc@google.com> X-Mailer: git-send-email 2.51.0.318.gd7df087d1a-goog Message-ID: <20250829000618.351013-19-seanjc@google.com> Subject: [RFC PATCH v2 18/18] KVM: TDX: Add macro to retry SEAMCALLs when forcing vCPUs out of guest From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Ira Weiny , Kai Huang , Michael Roth , Yan Zhao , Vishal Annapurve , Rick Edgecombe , Ackerley Tng Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add a macro to handle kicking vCPUs out of the guest and retrying SEAMCALLs on -EBUSY instead of providing small helpers to be used by each SEAMCALL. Wrapping the SEAMCALLs in a macro makes it a little harder to tease out which SEAMCALL is being made, but significantly reduces the amount of copy+paste code and makes it all but impossible to leave an elevated wait_for_sept_zap. Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/tdx.c | 72 ++++++++++++++---------------------------- 1 file changed, 23 insertions(+), 49 deletions(-) diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index aa740eeb1c2a..d6c9defad9cd 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -313,25 +313,24 @@ static void tdx_clear_page(struct page *page) __mb(); } =20 -static void tdx_no_vcpus_enter_start(struct kvm *kvm) -{ - struct kvm_tdx *kvm_tdx =3D to_kvm_tdx(kvm); - - lockdep_assert_held_write(&kvm->mmu_lock); - - WRITE_ONCE(kvm_tdx->wait_for_sept_zap, true); - - kvm_make_all_cpus_request(kvm, KVM_REQ_OUTSIDE_GUEST_MODE); -} - -static void tdx_no_vcpus_enter_stop(struct kvm *kvm) -{ - struct kvm_tdx *kvm_tdx =3D to_kvm_tdx(kvm); - - lockdep_assert_held_write(&kvm->mmu_lock); - - WRITE_ONCE(kvm_tdx->wait_for_sept_zap, false); -} +#define tdh_do_no_vcpus(tdh_func, kvm, args...) \ +({ \ + struct kvm_tdx *__kvm_tdx =3D to_kvm_tdx(kvm); \ + u64 __err; \ + \ + lockdep_assert_held_write(&kvm->mmu_lock); \ + \ + __err =3D tdh_func(args); \ + if (unlikely(tdx_operand_busy(__err))) { \ + WRITE_ONCE(__kvm_tdx->wait_for_sept_zap, true); \ + kvm_make_all_cpus_request(kvm, KVM_REQ_OUTSIDE_GUEST_MODE); \ + \ + __err =3D tdh_func(args); \ + \ + WRITE_ONCE(__kvm_tdx->wait_for_sept_zap, false); \ + } \ + __err; \ +}) =20 /* TDH.PHYMEM.PAGE.RECLAIM is allowed only when destroying the TD. */ static int __tdx_reclaim_page(struct page *page) @@ -1714,14 +1713,7 @@ static void tdx_track(struct kvm *kvm) if (unlikely(kvm_tdx->state !=3D TD_STATE_RUNNABLE)) return; =20 - err =3D tdh_mem_track(&kvm_tdx->td); - if (unlikely(tdx_operand_busy(err))) { - /* After no vCPUs enter, the second retry is expected to succeed */ - tdx_no_vcpus_enter_start(kvm); - err =3D tdh_mem_track(&kvm_tdx->td); - tdx_no_vcpus_enter_stop(kvm); - } - + err =3D tdh_do_no_vcpus(tdh_mem_track, kvm, &kvm_tdx->td); TDX_BUG_ON(err, TDH_MEM_TRACK, kvm); =20 kvm_make_all_cpus_request(kvm, KVM_REQ_OUTSIDE_GUEST_MODE); @@ -1773,14 +1765,8 @@ static void tdx_sept_remove_private_spte(struct kvm = *kvm, gfn_t gfn, if (KVM_BUG_ON(level !=3D PG_LEVEL_4K, kvm)) return; =20 - err =3D tdh_mem_range_block(&kvm_tdx->td, gpa, tdx_level, &entry, &level_= state); - if (unlikely(tdx_operand_busy(err))) { - /* After no vCPUs enter, the second retry is expected to succeed */ - tdx_no_vcpus_enter_start(kvm); - err =3D tdh_mem_range_block(&kvm_tdx->td, gpa, tdx_level, &entry, &level= _state); - tdx_no_vcpus_enter_stop(kvm); - } - + err =3D tdh_do_no_vcpus(tdh_mem_range_block, kvm, &kvm_tdx->td, gpa, + tdx_level, &entry, &level_state); if (TDX_BUG_ON_2(err, TDH_MEM_RANGE_BLOCK, entry, level_state, kvm)) return; =20 @@ -1795,20 +1781,8 @@ static void tdx_sept_remove_private_spte(struct kvm = *kvm, gfn_t gfn, * with other vcpu sept operation. * Race with TDH.VP.ENTER due to (0-step mitigation) and Guest TDCALLs. */ - err =3D tdh_mem_page_remove(&kvm_tdx->td, gpa, tdx_level, &entry, - &level_state); - - if (unlikely(tdx_operand_busy(err))) { - /* - * The second retry is expected to succeed after kicking off all - * other vCPUs and prevent them from invoking TDH.VP.ENTER. - */ - tdx_no_vcpus_enter_start(kvm); - err =3D tdh_mem_page_remove(&kvm_tdx->td, gpa, tdx_level, &entry, - &level_state); - tdx_no_vcpus_enter_stop(kvm); - } - + err =3D tdh_do_no_vcpus(tdh_mem_page_remove, kvm, &kvm_tdx->td, gpa, + tdx_level, &entry, &level_state); if (TDX_BUG_ON_2(err, TDH_MEM_PAGE_REMOVE, entry, level_state, kvm)) return; =20 --=20 2.51.0.318.gd7df087d1a-goog