linux-kernel - [PATCH v3 08/25] KVM: TDX: Return -EIO, not -EINVAL, on a KVM_BUG

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20251017003244.186495-9-seanjc@google.com>
Date: Thu, 16 Oct 2025 17:32:26 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>, 
	Tianrui Zhao <zhaotianrui@...ngson.cn>, Bibo Mao <maobibo@...ngson.cn>, 
	Huacai Chen <chenhuacai@...nel.org>, Madhavan Srinivasan <maddy@...ux.ibm.com>, 
	Anup Patel <anup@...infault.org>, Paul Walmsley <pjw@...nel.org>, 
	Palmer Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>, 
	Christian Borntraeger <borntraeger@...ux.ibm.com>, Janosch Frank <frankja@...ux.ibm.com>, 
	Claudio Imbrenda <imbrenda@...ux.ibm.com>, Sean Christopherson <seanjc@...gle.com>, 
	Paolo Bonzini <pbonzini@...hat.com>, "Kirill A. Shutemov" <kas@...nel.org>
Cc: linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev, 
	kvm@...r.kernel.org, loongarch@...ts.linux.dev, linux-mips@...r.kernel.org, 
	linuxppc-dev@...ts.ozlabs.org, kvm-riscv@...ts.infradead.org, 
	linux-riscv@...ts.infradead.org, x86@...nel.org, linux-coco@...ts.linux.dev, 
	linux-kernel@...r.kernel.org, Ira Weiny <ira.weiny@...el.com>, 
	Kai Huang <kai.huang@...el.com>, Michael Roth <michael.roth@....com>, 
	Yan Zhao <yan.y.zhao@...el.com>, Vishal Annapurve <vannapurve@...gle.com>, 
	Rick Edgecombe <rick.p.edgecombe@...el.com>, Ackerley Tng <ackerleytng@...gle.com>, 
	Binbin Wu <binbin.wu@...ux.intel.com>
Subject: [PATCH v3 08/25] KVM: TDX: Return -EIO, not -EINVAL, on a
 KVM_BUG_ON() condition

Return -EIO when a KVM_BUG_ON() is tripped, as KVM's ABI is to return -EIO
when a VM has been killed due to a KVM bug, not -EINVAL.  Note, many (all?)
of the affected paths never propagate the error code to userspace, i.e.
this is about internal consistency more than anything else.

Reviewed-by: Rick Edgecombe <rick.p.edgecombe@...el.com>
Reviewed-by: Ira Weiny <ira.weiny@...el.com>
Reviewed-by: Binbin Wu <binbin.wu@...ux.intel.com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/vmx/tdx.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index c3bae6b96dc4..c242d73b6a7b 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -1621,7 +1621,7 @@ static int tdx_mem_page_record_premap_cnt(struct kvm *kvm, gfn_t gfn,
 	struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
 
 	if (KVM_BUG_ON(kvm->arch.pre_fault_allowed, kvm))
-		return -EINVAL;
+		return -EIO;
 
 	/* nr_premapped will be decreased when tdh_mem_page_add() is called. */
 	atomic64_inc(&kvm_tdx->nr_premapped);
@@ -1635,7 +1635,7 @@ static int tdx_sept_set_private_spte(struct kvm *kvm, gfn_t gfn,
 
 	/* TODO: handle large pages. */
 	if (KVM_BUG_ON(level != PG_LEVEL_4K, kvm))
-		return -EINVAL;
+		return -EIO;
 
 	/*
 	 * Read 'pre_fault_allowed' before 'kvm_tdx->state'; see matching
@@ -1658,10 +1658,10 @@ static int tdx_sept_drop_private_spte(struct kvm *kvm, gfn_t gfn,
 
 	/* TODO: handle large pages. */
 	if (KVM_BUG_ON(level != PG_LEVEL_4K, kvm))
-		return -EINVAL;
+		return -EIO;
 
 	if (KVM_BUG_ON(!is_hkid_assigned(kvm_tdx), kvm))
-		return -EINVAL;
+		return -EIO;
 
 	/*
 	 * When zapping private page, write lock is held. So no race condition
@@ -1846,7 +1846,7 @@ static int tdx_sept_free_private_spt(struct kvm *kvm, gfn_t gfn,
 	 * and slot move/deletion.
 	 */
 	if (KVM_BUG_ON(is_hkid_assigned(kvm_tdx), kvm))
-		return -EINVAL;
+		return -EIO;
 
 	/*
 	 * The HKID assigned to this TD was already freed and cache was
@@ -1867,7 +1867,7 @@ static int tdx_sept_remove_private_spte(struct kvm *kvm, gfn_t gfn,
 	 * there can't be anything populated in the private EPT.
 	 */
 	if (KVM_BUG_ON(!is_hkid_assigned(to_kvm_tdx(kvm)), kvm))
-		return -EINVAL;
+		return -EIO;
 
 	ret = tdx_sept_zap_private_spte(kvm, gfn, level, page);
 	if (ret <= 0)
-- 
2.51.0.858.gf9c4a03a3a-goog