Re: [PATCH RFC v9 03/51] KVM: x86: Use full 64-bit error code for kvm_mmu_do_page_fault
From: Isaku Yamahata <hidden>
Date: 2023-06-14 14:24:36
Also in:
kvm, linux-crypto, linux-mm, lkml
Subsystem:
kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
On Sun, Jun 11, 2023 at 11:25:11PM -0500, Michael Roth [off-list ref] wrote:
quoted hunk ↗ jump to hunk
The upper bits will be needed in some cases to distinguish between nested page faults for private/shared pages, so pass along the full 64-bit value. Signed-off-by: Michael Roth <redacted> --- arch/x86/kvm/mmu/mmu.c | 3 +-- arch/x86/kvm/mmu/mmu_internal.h | 4 ++-- 2 files changed, 3 insertions(+), 4 deletions(-)diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index c54672ad6cbc..0d3983b9aa7e 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c@@ -5829,8 +5829,7 @@ 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 f1786698ae00..780b91e1da9f 100644 --- a/arch/x86/kvm/mmu/mmu_internal.h +++ b/arch/x86/kvm/mmu/mmu_internal.h@@ -283,11 +283,11 @@ 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, - .error_code = err, + .error_code = lower_32_bits(err), .exec = err & PFERR_FETCH_MASK, .write = err & PFERR_WRITE_MASK, .present = err & PFERR_PRESENT_MASK,-- 2.25.1
Hi. I'd like to pass around 64bit for TDX and come up with the following one.
Does it work for you?
From 53273b67e9be09129d35ac00cf9ce739d3fb4e2c Mon Sep 17 00:00:00 2001
Message-Id: [off-list ref]
From: Isaku Yamahata <redacted>
Date: Fri, 17 Mar 2023 12:58:42 -0700
Subject: [PATCH] KVM: x86/mmu: Pass round full 64-bit error code for the KVM
page fault
In some cases the full 64-bit error code for the KVM page fault will be
needed to make this determination, so also update kvm_mmu_do_page_fault()
to accept the full 64-bit value so it can be plumbed through to the
callback.
The upper 32 bits of error code is discarded at kvm_mmu_page_fault()
by lower_32_bits(). Now it's passed down as full 64 bits. It turns out
that only FNAME(page_fault) depends on it. Move lower_32_bits() into
FNAME(page_fault).
The accesses of fault->error_code are as follows
- FNAME(page_fault): change to explicitly use lower_32_bits()
- kvm_tdp_page_fault(): explicit mask with PFERR_LEVEL_MASK
- kvm_mmu_page_fault(): explicit mask with PFERR_RSVD_MASK,
PFERR_NESTED_GUEST_PAGE
- mmutrace: changed u32 -> u64
- pgprintk(): change %x -> %llx
Signed-off-by: Isaku Yamahata <redacted>
---
arch/x86/kvm/mmu.h | 2 +-
arch/x86/kvm/mmu/mmu.c | 7 +++----
arch/x86/kvm/mmu/mmu_internal.h | 4 ++--
arch/x86/kvm/mmu/mmutrace.h | 2 +-
arch/x86/kvm/mmu/paging_tmpl.h | 4 ++--
5 files changed, 9 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 6cc2558e977d..b6c9c2e27d0b 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h@@ -176,7 +176,7 @@ static inline void kvm_mmu_refresh_passthrough_bits(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); + u64 error_code, int max_level); /* * Check if a given access (described through the I/D, W/R and U/S bits of a
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 2c6d9d8d2c10..e4457eaa10a9 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c@@ -4941,7 +4941,7 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault static int nonpaging_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) { - pgprintk("%s: gva %llx error %x\n", __func__, fault->addr, fault->error_code); + pgprintk("%s: gva %llx error %llx\n", __func__, fault->addr, fault->error_code); /* This path builds a PAE pagetable, we can map 2mb pages at maximum. */ fault->max_level = PG_LEVEL_2M;
@@ -5062,7 +5062,7 @@ int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) } kvm_pfn_t kvm_mmu_map_tdp_page(struct kvm_vcpu *vcpu, gpa_t gpa, - u32 error_code, int max_level) + u64 error_code, int max_level) { int r; struct kvm_page_fault fault = (struct kvm_page_fault) {
@@ -6317,8 +6317,7 @@ 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 2d8a5df56f20..979fd7c26610 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h@@ -342,7 +342,7 @@ 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. */
@@ -437,7 +437,7 @@ 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 2d7555381955..2e77883c92f6 100644
--- a/arch/x86/kvm/mmu/mmutrace.h
+++ b/arch/x86/kvm/mmu/mmutrace.h@@ -261,7 +261,7 @@ 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 d87f95245ee9..8aeafd9178ac 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h@@ -758,7 +758,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault struct guest_walker walker; int r; - pgprintk("%s: addr %llx err %x\n", __func__, fault->addr, fault->error_code); + pgprintk("%s: addr %llx err %llx\n", __func__, fault->addr, fault->error_code); WARN_ON_ONCE(fault->is_tdp); /*
@@ -767,7 +767,7 @@ 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
--
Isaku Yamahata <isaku.yamahata@gmail.com>