diff mbox series

[v11,06/35] KVM: x86/mmu: Pass around full 64-bit error code for KVM page faults

Message ID 20231230172351.574091-7-michael.roth@amd.com
State New
Headers
Series [v11,01/35] KVM: Add hugepage support for dedicated guest memory |

Commit Message

Michael Roth Dec. 30, 2023, 5:23 p.m. UTC 
  In some cases the full 64-bit error code for the KVM page fault will be
needed to determine things like whether or not a fault was for a private
or shared guest page, so update related code to accept the full 64-bit
value so it can be plumbed all the way through to where it is needed.

The accessors of fault->error_code are changed as follows:

- FNAME(page_fault): change to explicitly use lower_32_bits() since that
                     is no longer done in kvm_mmu_page_fault()
- kvm_mmu_page_fault(): explicit mask with PFERR_RSVD_MASK,
                        PFERR_NESTED_GUEST_PAGE
- mmutrace: changed u32 -> u64

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Link: https://lore.kernel.org/kvm/20230612042559.375660-1-michael.roth@amd.com/T/#mbd0b20c9a2cf50319d5d2a27b63f73c772112076
[mdr: drop references/changes to code not in current gmem tree, update
      commit message]
Signed-off-by: Michael Roth <michael.roth@amd.com>
---
 arch/x86/kvm/mmu/mmu.c          | 3 +--
 arch/x86/kvm/mmu/mmu_internal.h | 4 ++--
 arch/x86/kvm/mmu/mmutrace.h     | 2 +-
 arch/x86/kvm/mmu/paging_tmpl.h  | 2 +-
 4 files changed, 5 insertions(+), 6 deletions(-)

Comments

Sean Christopherson Feb. 6, 2024, 8:51 p.m. UTC | #1 
On Sat, Dec 30, 2023, Michael Roth wrote:
> In some cases the full 64-bit error code for the KVM page fault will be
> needed to determine things like whether or not a fault was for a private
> or shared guest page, so update related code to accept the full 64-bit
> value so it can be plumbed all the way through to where it is needed.
> 
> The accessors of fault->error_code are changed as follows:
> 
> - FNAME(page_fault): change to explicitly use lower_32_bits() since that
>                      is no longer done in kvm_mmu_page_fault()
> - kvm_mmu_page_fault(): explicit mask with PFERR_RSVD_MASK,
>                         PFERR_NESTED_GUEST_PAGE
> - mmutrace: changed u32 -> u64
> 
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> Link: https://lore.kernel.org/kvm/20230612042559.375660-1-michael.roth@amd.com/T/#mbd0b20c9a2cf50319d5d2a27b63f73c772112076
> [mdr: drop references/changes to code not in current gmem tree, update
>       commit message]
> Signed-off-by: Michael Roth <michael.roth@amd.com>

I assume Isaku is the original author?  If so, that's missing from this patch.
Paolo Bonzini Feb. 12, 2024, 10 a.m. UTC | #2 
On Tue, Feb 6, 2024 at 9:52 PM Sean Christopherson <seanjc@google.com> wrote:
>
> On Sat, Dec 30, 2023, Michael Roth wrote:
> > In some cases the full 64-bit error code for the KVM page fault will be
> > needed to determine things like whether or not a fault was for a private
> > or shared guest page, so update related code to accept the full 64-bit
> > value so it can be plumbed all the way through to where it is needed.
> >
> > The accessors of fault->error_code are changed as follows:
> >
> > - FNAME(page_fault): change to explicitly use lower_32_bits() since that
> >                      is no longer done in kvm_mmu_page_fault()
> > - kvm_mmu_page_fault(): explicit mask with PFERR_RSVD_MASK,
> >                         PFERR_NESTED_GUEST_PAGE
> > - mmutrace: changed u32 -> u64
> >
> > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> > Link: https://lore.kernel.org/kvm/20230612042559.375660-1-michael.roth@amd.com/T/#mbd0b20c9a2cf50319d5d2a27b63f73c772112076
> > [mdr: drop references/changes to code not in current gmem tree, update
> >       commit message]
> > Signed-off-by: Michael Roth <michael.roth@amd.com>
>
> I assume Isaku is the original author?  If so, that's missing from this patch.

The root of this patch seem to be in a reply to "KVM: x86: Add
'fault_is_private' x86 op"
(https://patchew.org/linux/20230220183847.59159-1-michael.roth@amd.com/20230220183847.59159-2-michael.roth@amd.com/),
so yes.

Paolo
Michael Roth Feb. 12, 2024, 4:42 p.m. UTC | #3 
On Mon, Feb 12, 2024 at 11:00:27AM +0100, Paolo Bonzini wrote:
> On Tue, Feb 6, 2024 at 9:52 PM Sean Christopherson <seanjc@google.com> wrote:
> >
> > On Sat, Dec 30, 2023, Michael Roth wrote:
> > > In some cases the full 64-bit error code for the KVM page fault will be
> > > needed to determine things like whether or not a fault was for a private
> > > or shared guest page, so update related code to accept the full 64-bit
> > > value so it can be plumbed all the way through to where it is needed.
> > >
> > > The accessors of fault->error_code are changed as follows:
> > >
> > > - FNAME(page_fault): change to explicitly use lower_32_bits() since that
> > >                      is no longer done in kvm_mmu_page_fault()
> > > - kvm_mmu_page_fault(): explicit mask with PFERR_RSVD_MASK,
> > >                         PFERR_NESTED_GUEST_PAGE
> > > - mmutrace: changed u32 -> u64
> > >
> > > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> > > Link: https://lore.kernel.org/kvm/20230612042559.375660-1-michael.roth@amd.com/T/#mbd0b20c9a2cf50319d5d2a27b63f73c772112076
> > > [mdr: drop references/changes to code not in current gmem tree, update
> > >       commit message]
> > > Signed-off-by: Michael Roth <michael.roth@amd.com>
> >
> > I assume Isaku is the original author?  If so, that's missing from this patch.
> 
> The root of this patch seem to be in a reply to "KVM: x86: Add
> 'fault_is_private' x86 op"
> (https://patchew.org/linux/20230220183847.59159-1-michael.roth@amd.com/20230220183847.59159-2-michael.roth@amd.com/),
> so yes.

Yes this is Isaku's patch, I think the authorship got mangled during a rebase.
I'll make sure to get that fixed up.

-Mike

> 
> Paolo
>
diff mbox series

Patch

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 3c844e428684..d3fbfe0686a0 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5813,8 +5813,7 @@  int noinline kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 err
 	}
 
 	if (r == RET_PF_INVALID) {
-		r = kvm_mmu_do_page_fault(vcpu, cr2_or_gpa,
-					  lower_32_bits(error_code), false,
+		r = kvm_mmu_do_page_fault(vcpu, cr2_or_gpa, error_code, false,
 					  &emulation_type);
 		if (KVM_BUG_ON(r == RET_PF_INVALID, vcpu->kvm))
 			return -EIO;
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index 0669a8a668ca..21f55e8b4dc6 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -190,7 +190,7 @@  static inline bool is_nx_huge_page_enabled(struct kvm *kvm)
 struct kvm_page_fault {
 	/* arguments to kvm_mmu_do_page_fault.  */
 	const gpa_t addr;
-	const u32 error_code;
+	const u64 error_code;
 	const bool prefetch;
 
 	/* Derived from error_code.  */
@@ -280,7 +280,7 @@  enum {
 };
 
 static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
-					u32 err, bool prefetch, int *emulation_type)
+					u64 err, bool prefetch, int *emulation_type)
 {
 	struct kvm_page_fault fault = {
 		.addr = cr2_or_gpa,
diff --git a/arch/x86/kvm/mmu/mmutrace.h b/arch/x86/kvm/mmu/mmutrace.h
index ae86820cef69..195d98bc8de8 100644
--- a/arch/x86/kvm/mmu/mmutrace.h
+++ b/arch/x86/kvm/mmu/mmutrace.h
@@ -260,7 +260,7 @@  TRACE_EVENT(
 	TP_STRUCT__entry(
 		__field(int, vcpu_id)
 		__field(gpa_t, cr2_or_gpa)
-		__field(u32, error_code)
+		__field(u64, error_code)
 		__field(u64 *, sptep)
 		__field(u64, old_spte)
 		__field(u64, new_spte)
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 4d4e98fe4f35..c418f3b1cfca 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -787,7 +787,7 @@  static int FNAME(page_fault)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
 	 * The bit needs to be cleared before walking guest page tables.
 	 */
 	r = FNAME(walk_addr)(&walker, vcpu, fault->addr,
-			     fault->error_code & ~PFERR_RSVD_MASK);
+			     lower_32_bits(fault->error_code) & ~PFERR_RSVD_MASK);
 
 	/*
 	 * The page is not mapped by the guest.  Let the guest handle it.