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

Michael Roth
2023-12-30T17:35:52Z

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(-)

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.
--
2.25.1