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    SubjectRE: [PATCH Part2 v6 41/49] KVM: SVM: Add support to handle the RMP nested page fault
    Date
    [AMD Official Use Only - General]

    Yes, this is fixed in 5.19 rebase.

    Thanks,
    Ashish

    -----Original Message-----
    From: Jarkko Sakkinen <jarkko@kernel.org>
    Sent: Tuesday, July 12, 2022 7:49 AM
    To: Kalra, Ashish <Ashish.Kalra@amd.com>
    Cc: x86@kernel.org; linux-kernel@vger.kernel.org; kvm@vger.kernel.org; linux-coco@lists.linux.dev; linux-mm@kvack.org; linux-crypto@vger.kernel.org; tglx@linutronix.de; mingo@redhat.com; jroedel@suse.de; Lendacky, Thomas <Thomas.Lendacky@amd.com>; hpa@zytor.com; ardb@kernel.org; pbonzini@redhat.com; seanjc@google.com; vkuznets@redhat.com; jmattson@google.com; luto@kernel.org; dave.hansen@linux.intel.com; slp@redhat.com; pgonda@google.com; peterz@infradead.org; srinivas.pandruvada@linux.intel.com; rientjes@google.com; dovmurik@linux.ibm.com; tobin@ibm.com; bp@alien8.de; Roth, Michael <Michael.Roth@amd.com>; vbabka@suse.cz; kirill@shutemov.name; ak@linux.intel.com; tony.luck@intel.com; marcorr@google.com; sathyanarayanan.kuppuswamy@linux.intel.com; alpergun@google.com; dgilbert@redhat.com
    Subject: Re: [PATCH Part2 v6 41/49] KVM: SVM: Add support to handle the RMP nested page fault

    On Tue, Jul 12, 2022 at 03:45:13PM +0300, Jarkko Sakkinen wrote:
    > On Tue, Jul 12, 2022 at 03:34:00PM +0300, Jarkko Sakkinen wrote:
    > > On Mon, Jun 20, 2022 at 11:13:03PM +0000, Ashish Kalra wrote:
    > > > From: Brijesh Singh <brijesh.singh@amd.com>
    > > >
    > > > When SEV-SNP is enabled in the guest, the hardware places
    > > > restrictions on all memory accesses based on the contents of the
    > > > RMP table. When hardware encounters RMP check failure caused by
    > > > the guest memory access it raises the #NPF. The error code
    > > > contains additional information on the access type. See the APM volume 2 for additional information.
    > > >
    > > > Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
    > > > ---
    > > > arch/x86/kvm/svm/sev.c | 76
    > > > ++++++++++++++++++++++++++++++++++++++++++
    > > > arch/x86/kvm/svm/svm.c | 14 +++++---
    > > > 2 files changed, 86 insertions(+), 4 deletions(-)
    > > >
    > > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index
    > > > 4ed90331bca0..7fc0fad87054 100644
    > > > --- a/arch/x86/kvm/svm/sev.c
    > > > +++ b/arch/x86/kvm/svm/sev.c
    > > > @@ -4009,3 +4009,79 @@ void sev_post_unmap_gfn(struct kvm *kvm,
    > > > gfn_t gfn, kvm_pfn_t pfn)
    > > >
    > > > spin_unlock(&sev->psc_lock);
    > > > }
    > > > +
    > > > +void handle_rmp_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u64
    > > > +error_code) {
    > > > + int rmp_level, npt_level, rc, assigned;
    > > > + struct kvm *kvm = vcpu->kvm;
    > > > + gfn_t gfn = gpa_to_gfn(gpa);
    > > > + bool need_psc = false;
    > > > + enum psc_op psc_op;
    > > > + kvm_pfn_t pfn;
    > > > + bool private;
    > > > +
    > > > + write_lock(&kvm->mmu_lock);
    > > > +
    > > > + if (unlikely(!kvm_mmu_get_tdp_walk(vcpu, gpa, &pfn,
    > > > +&npt_level)))
    > >
    > > This function does not exist. Should it be kvm_mmu_get_tdp_page?
    >
    > Ugh, ignore that.
    >
    > This the actual issue:
    >
    > $ git grep kvm_mmu_get_tdp_walk
    > arch/x86/kvm/mmu/mmu.c:bool kvm_mmu_get_tdp_walk(struct kvm_vcpu
    > *vcpu, gpa_t gpa, kvm_pfn_t *pfn, int *level) arch/x86/kvm/mmu/mmu.c:EXPORT_SYMBOL_GPL(kvm_mmu_get_tdp_walk);
    > arch/x86/kvm/svm/sev.c: rc = kvm_mmu_get_tdp_walk(vcpu, gpa, &pfn, &npt_level);
    >
    > It's not declared in any header.

    diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index 0e1f4d92b89b..33267f619e61 100644
    --- a/arch/x86/kvm/mmu.h
    +++ b/arch/x86/kvm/mmu.h
    @@ -164,6 +164,8 @@ static inline void kvm_mmu_load_pgd(struct kvm_vcpu *vcpu) kvm_pfn_t kvm_mmu_map_tdp_page(struct kvm_vcpu *vcpu, gpa_t gpa,
    u32 error_code, int max_level);

    +bool kvm_mmu_get_tdp_walk(struct kvm_vcpu *vcpu, gpa_t gpa, kvm_pfn_t *pfn, int *level):
    +
    /*
    * Check if a given access (described through the I/D, W/R and U/S bits of a
    * page fault error code pfec) causes a permission fault with the given PTE

    BTW, kvm_mmu_map_tdp_page() ought to be in single line since it's less than
    100 characters.

    BR, Jarkko

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