From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Subject: [PATCH 08/17] KVM: x86/mmu: check for invalid async page faults involving private memory
Date: Tue, 7 May 2024 11:58:08 -0400 [thread overview]
Message-ID: <20240507155817.3951344-9-pbonzini@redhat.com> (raw)
In-Reply-To: <20240507155817.3951344-1-pbonzini@redhat.com>
Right now the error code is not used when an async page fault is completed.
This is not a problem in the current code, but it is untidy. For protected
VMs, we will also need to check that the page attributes match the current
state of the page, because asynchronous page faults can only occur on
shared pages (private pages go through kvm_faultin_pfn_private() instead of
__gfn_to_pfn_memslot()).
Start by piping the error code from kvm_arch_setup_async_pf() to
kvm_arch_async_page_ready() via the architecture-specific async page
fault data. For now, it can be used to assert that there are no
async page faults on private memory.
Extracted from a patch by Isaku Yamahata.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/mmu/mmu.c | 18 +++++++++++-------
2 files changed, 12 insertions(+), 7 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 0dc755a6dc0c..9d6368512be6 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1851,6 +1851,7 @@ struct kvm_arch_async_pf {
gfn_t gfn;
unsigned long cr3;
bool direct_map;
+ u64 error_code;
};
extern u32 __read_mostly kvm_nr_uret_msrs;
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index eb041acec2dc..d52794663290 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4207,24 +4207,28 @@ static u32 alloc_apf_token(struct kvm_vcpu *vcpu)
return (vcpu->arch.apf.id++ << 12) | vcpu->vcpu_id;
}
-static bool kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
- gfn_t gfn)
+static bool kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu,
+ struct kvm_page_fault *fault)
{
struct kvm_arch_async_pf arch;
arch.token = alloc_apf_token(vcpu);
- arch.gfn = gfn;
+ arch.gfn = fault->gfn;
+ arch.error_code = fault->error_code;
arch.direct_map = vcpu->arch.mmu->root_role.direct;
arch.cr3 = kvm_mmu_get_guest_pgd(vcpu, vcpu->arch.mmu);
- return kvm_setup_async_pf(vcpu, cr2_or_gpa,
- kvm_vcpu_gfn_to_hva(vcpu, gfn), &arch);
+ return kvm_setup_async_pf(vcpu, fault->addr,
+ kvm_vcpu_gfn_to_hva(vcpu, fault->gfn), &arch);
}
void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
{
int r;
+ if (WARN_ON_ONCE(work->arch.error_code & PFERR_PRIVATE_ACCESS))
+ return;
+
if ((vcpu->arch.mmu->root_role.direct != work->arch.direct_map) ||
work->wakeup_all)
return;
@@ -4237,7 +4241,7 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
work->arch.cr3 != kvm_mmu_get_guest_pgd(vcpu, vcpu->arch.mmu))
return;
- kvm_mmu_do_page_fault(vcpu, work->cr2_or_gpa, 0, true, NULL);
+ kvm_mmu_do_page_fault(vcpu, work->cr2_or_gpa, work->arch.error_code, true, NULL);
}
static inline u8 kvm_max_level_for_order(int order)
@@ -4334,7 +4338,7 @@ static int __kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
trace_kvm_async_pf_repeated_fault(fault->addr, fault->gfn);
kvm_make_request(KVM_REQ_APF_HALT, vcpu);
return RET_PF_RETRY;
- } else if (kvm_arch_setup_async_pf(vcpu, fault->addr, fault->gfn)) {
+ } else if (kvm_arch_setup_async_pf(vcpu, fault)) {
return RET_PF_RETRY;
}
}
--
2.43.0
next prev parent reply other threads:[~2024-05-07 15:58 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-07 15:58 [PATCH v2 00/17] KVM: x86/mmu: Page fault and MMIO cleanups Paolo Bonzini
2024-05-07 15:58 ` [PATCH 01/17] KVM: x86/mmu: Exit to userspace with -EFAULT if private fault hits emulation Paolo Bonzini
2024-05-13 5:25 ` Xiaoyao Li
2024-05-07 15:58 ` [PATCH 02/17] KVM: x86: Remove separate "bit" defines for page fault error code masks Paolo Bonzini
2024-05-13 5:29 ` Xiaoyao Li
2024-05-07 15:58 ` [PATCH 03/17] KVM: x86: Define more SEV+ page fault error bits/flags for #NPF Paolo Bonzini
2024-05-07 15:58 ` [PATCH 04/17] KVM: x86: Move synthetic PFERR_* sanity checks to SVM's #NPF handler Paolo Bonzini
2024-05-13 5:50 ` Xiaoyao Li
2024-05-13 17:31 ` Sean Christopherson
2024-05-14 4:25 ` Xiaoyao Li
2024-05-14 15:32 ` Sean Christopherson
2024-05-15 1:03 ` Xiaoyao Li
2024-05-07 15:58 ` [PATCH 05/17] KVM: x86/mmu: Pass full 64-bit error code when handling page faults Paolo Bonzini
2024-05-07 15:58 ` [PATCH 06/17] KVM: x86/mmu: WARN if upper 32 bits of legacy #PF error code are non-zero Paolo Bonzini
2024-05-07 15:58 ` [PATCH 07/17] KVM: x86/mmu: Use synthetic page fault error code to indicate private faults Paolo Bonzini
2024-05-13 5:56 ` Xiaoyao Li
2024-05-07 15:58 ` Paolo Bonzini [this message]
2024-05-07 15:58 ` [PATCH 09/17] KVM: x86/mmu: WARN and skip MMIO cache on private, reserved page faults Paolo Bonzini
2024-05-13 6:15 ` Xiaoyao Li
2024-05-07 15:58 ` [PATCH 10/17] KVM: x86/mmu: Move private vs. shared check above slot validity checks Paolo Bonzini
2024-05-13 6:22 ` Xiaoyao Li
2024-05-07 15:58 ` [PATCH 11/17] KVM: x86/mmu: Don't force emulation of L2 accesses to non-APIC internal slots Paolo Bonzini
2024-05-07 15:58 ` [PATCH 12/17] KVM: x86/mmu: Explicitly disallow private accesses to emulated MMIO Paolo Bonzini
2024-05-13 6:26 ` Xiaoyao Li
2024-05-07 15:58 ` [PATCH 13/17] KVM: x86/mmu: Move slot checks from __kvm_faultin_pfn() to kvm_faultin_pfn() Paolo Bonzini
2024-05-13 6:27 ` Xiaoyao Li
2024-05-07 15:58 ` [PATCH 14/17] KVM: x86/mmu: Handle no-slot faults at the beginning of kvm_faultin_pfn() Paolo Bonzini
2024-05-13 6:28 ` Xiaoyao Li
2024-05-07 15:58 ` [PATCH 15/17] KVM: x86/mmu: Set kvm_page_fault.hva to KVM_HVA_ERR_BAD for "no slot" faults Paolo Bonzini
2024-05-13 6:28 ` Xiaoyao Li
2024-05-07 15:58 ` [PATCH 16/17] KVM: x86/mmu: Initialize kvm_page_fault's pfn and hva to error values Paolo Bonzini
2024-05-13 6:29 ` Xiaoyao Li
2024-05-07 15:58 ` [PATCH 17/17] KVM: x86/mmu: Sanity check that __kvm_faultin_pfn() doesn't create noslot pfns Paolo Bonzini
2024-05-13 6:40 ` Xiaoyao Li
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