[PATCH 09/15] KVM: x86/mmu: Introduce status parameter to page walker

From: Nikolas Wipper
Date: Tue Sep 10 2024 - 11:27:01 EST

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Introduce the status parameter to walk_addr_generic() which is used in
later patches to provide the caller with information on whether setting
the accessed/dirty bits succeeded.

No functional change intended.

Signed-off-by: Nikolas Wipper <nikwip@xxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/hyperv.c | 2 +-
arch/x86/kvm/mmu.h | 8 +++++---
arch/x86/kvm/mmu/mmu.c | 5 +++--
arch/x86/kvm/mmu/paging_tmpl.h | 26 ++++++++++++++++----------
arch/x86/kvm/x86.c | 25 ++++++++++++++-----------
6 files changed, 40 insertions(+), 28 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index cd2c391d6a24..1c5aaf55c683 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -460,7 +460,7 @@ struct kvm_mmu {
struct x86_exception *fault);
gpa_t (*gva_to_gpa)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
gpa_t gva_or_gpa, u64 access, u64 flags,
- struct x86_exception *exception);
+ struct x86_exception *exception, u16 *status);
int (*sync_spte)(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp, int i);
struct kvm_mmu_root_info root;
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index b237231ace61..30d5b86bc306 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -2037,7 +2037,7 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc)
*/
if (!hc->fast && is_guest_mode(vcpu)) {
hc->ingpa = translate_nested_gpa(vcpu, hc->ingpa, 0,
- PWALK_SET_ALL, NULL);
+ PWALK_SET_ALL, NULL, NULL);
if (unlikely(hc->ingpa == INVALID_GPA))
return HV_STATUS_INVALID_HYPERCALL_INPUT;
}
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 35030f6466b5..272ce93f855f 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -275,15 +275,17 @@ static inline void kvm_update_page_stats(struct kvm *kvm, int level, int count)
}

gpa_t translate_nested_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u64 access,
- u64 flags, struct x86_exception *exception);
+ u64 flags, struct x86_exception *exception,
+ u16 *status);

static inline gpa_t kvm_translate_gpa(struct kvm_vcpu *vcpu,
struct kvm_mmu *mmu,
gpa_t gpa, u64 access, u64 flags,
- struct x86_exception *exception)
+ struct x86_exception *exception,
+ u16 *status)
{
if (mmu != &vcpu->arch.nested_mmu)
return gpa;
- return translate_nested_gpa(vcpu, gpa, access, flags, exception);
+ return translate_nested_gpa(vcpu, gpa, access, flags, exception, status);
}
#endif
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 50c635142bf7..2ab0437edf54 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4103,11 +4103,12 @@ void kvm_mmu_sync_prev_roots(struct kvm_vcpu *vcpu)

static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
gpa_t vaddr, u64 access, u64 flags,
- struct x86_exception *exception)
+ struct x86_exception *exception, u16 *status)
{
if (exception)
exception->error_code = 0;
- return kvm_translate_gpa(vcpu, mmu, vaddr, access, flags, exception);
+ return kvm_translate_gpa(vcpu, mmu, vaddr, access, flags, exception,
+ status);
}

static bool mmio_info_in_cache(struct kvm_vcpu *vcpu, u64 addr, bool direct)
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 2cc40fd17f53..985a19dda603 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -197,7 +197,8 @@ static inline unsigned FNAME(gpte_access)(u64 gpte)
static int FNAME(update_accessed_dirty_bits)(struct kvm_vcpu *vcpu,
struct kvm_mmu *mmu,
struct guest_walker *walker,
- gpa_t addr, int write_fault)
+ gpa_t addr, int write_fault,
+ u16 *status)
{
unsigned level, index;
pt_element_t pte, orig_pte;
@@ -301,7 +302,8 @@ static inline bool FNAME(is_last_gpte)(struct kvm_mmu *mmu,
*/
static int FNAME(walk_addr_generic)(struct guest_walker *walker,
struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
- gpa_t addr, u64 access, u64 flags)
+ gpa_t addr, u64 access, u64 flags,
+ u16 *status)
{
int ret;
pt_element_t pte;
@@ -344,6 +346,9 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,

walker->fault.flags = 0;

+ if (status)
+ *status = 0;
+
/*
* FIXME: on Intel processors, loads of the PDPTE registers for PAE paging
* by the MOV to CR instruction are treated as reads and do not cause the
@@ -383,7 +388,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,

real_gpa = kvm_translate_gpa(vcpu, mmu, gfn_to_gpa(table_gfn),
nested_access, flags,
- &walker->fault);
+ &walker->fault, status);

/*
* FIXME: This can happen if emulation (for of an INS/OUTS
@@ -453,8 +458,8 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
gfn += pse36_gfn_delta(pte);
#endif

- real_gpa = kvm_translate_gpa(vcpu, mmu, gfn_to_gpa(gfn), access,
- flags, &walker->fault);
+ real_gpa = kvm_translate_gpa(vcpu, mmu, gfn_to_gpa(gfn), access, flags,
+ &walker->fault, status);
if (real_gpa == INVALID_GPA)
goto late_exit;

@@ -473,7 +478,8 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,

if (unlikely(set_accessed && !accessed_dirty)) {
ret = FNAME(update_accessed_dirty_bits)(vcpu, mmu, walker, addr,
- write_fault && set_dirty);
+ write_fault && set_dirty,
+ status);
if (unlikely(ret < 0))
goto error;
else if (ret)
@@ -538,7 +544,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
*/
++walker->level;
FNAME(update_accessed_dirty_bits)(vcpu, mmu, walker, addr,
- false);
+ false, status);
--walker->level;
}
return 0;
@@ -548,7 +554,7 @@ static int FNAME(walk_addr)(struct guest_walker *walker, struct kvm_vcpu *vcpu,
gpa_t addr, u64 access, u64 flags)
{
return FNAME(walk_addr_generic)(walker, vcpu, vcpu->arch.mmu, addr,
- access, flags);
+ access, flags, NULL);
}

static bool
@@ -891,7 +897,7 @@ static gpa_t FNAME(get_level1_sp_gpa)(struct kvm_mmu_page *sp)
/* Note, @addr is a GPA when gva_to_gpa() translates an L2 GPA to an L1 GPA. */
static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
gpa_t addr, u64 access, u64 flags,
- struct x86_exception *exception)
+ struct x86_exception *exception, u16 *status)
{
struct guest_walker walker;
gpa_t gpa = INVALID_GPA;
@@ -902,7 +908,7 @@ static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
WARN_ON_ONCE((addr >> 32) && mmu == vcpu->arch.walk_mmu);
#endif

- r = FNAME(walk_addr_generic)(&walker, vcpu, mmu, addr, access, flags);
+ r = FNAME(walk_addr_generic)(&walker, vcpu, mmu, addr, access, flags, status);

if (r) {
gpa = gfn_to_gpa(walker.gfn);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 32e81cd502ee..be696b60aba6 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1068,7 +1068,7 @@ int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3)
*/
real_gpa = kvm_translate_gpa(vcpu, mmu, gfn_to_gpa(pdpt_gfn),
PFERR_USER_MASK | PFERR_WRITE_MASK,
- PWALK_SET_ALL, NULL);
+ PWALK_SET_ALL, NULL, NULL);
if (real_gpa == INVALID_GPA)
return 0;

@@ -7561,7 +7561,8 @@ void kvm_get_segment(struct kvm_vcpu *vcpu,
}

gpa_t translate_nested_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u64 access,
- u64 flags, struct x86_exception *exception)
+ u64 flags, struct x86_exception *exception,
+ u16 *status)
{
struct kvm_mmu *mmu = vcpu->arch.mmu;
gpa_t t_gpa;
@@ -7570,7 +7571,8 @@ gpa_t translate_nested_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u64 access,

/* NPT walks are always user-walks */
access |= PFERR_USER_MASK;
- t_gpa = mmu->gva_to_gpa(vcpu, mmu, gpa, access, flags, exception);
+ t_gpa = mmu->gva_to_gpa(vcpu, mmu, gpa, access, flags, exception,
+ status);

return t_gpa;
}
@@ -7582,7 +7584,7 @@ gpa_t kvm_mmu_gva_to_gpa_read(struct kvm_vcpu *vcpu, gva_t gva,

u64 access = (kvm_x86_call(get_cpl)(vcpu) == 3) ? PFERR_USER_MASK : 0;
return mmu->gva_to_gpa(vcpu, mmu, gva, access, PWALK_SET_ALL,
- exception);
+ exception, NULL);
}
EXPORT_SYMBOL_GPL(kvm_mmu_gva_to_gpa_read);

@@ -7594,7 +7596,7 @@ gpa_t kvm_mmu_gva_to_gpa_write(struct kvm_vcpu *vcpu, gva_t gva,
u64 access = (kvm_x86_call(get_cpl)(vcpu) == 3) ? PFERR_USER_MASK : 0;
access |= PFERR_WRITE_MASK;
return mmu->gva_to_gpa(vcpu, mmu, gva, access, PWALK_SET_ALL,
- exception);
+ exception, NULL);
}
EXPORT_SYMBOL_GPL(kvm_mmu_gva_to_gpa_write);

@@ -7604,7 +7606,7 @@ gpa_t kvm_mmu_gva_to_gpa_system(struct kvm_vcpu *vcpu, gva_t gva,
{
struct kvm_mmu *mmu = vcpu->arch.walk_mmu;

- return mmu->gva_to_gpa(vcpu, mmu, gva, 0, PWALK_SET_ALL, exception);
+ return mmu->gva_to_gpa(vcpu, mmu, gva, 0, PWALK_SET_ALL, exception, NULL);
}

static int kvm_read_guest_virt_helper(gva_t addr, void *val, unsigned int bytes,
@@ -7617,7 +7619,7 @@ static int kvm_read_guest_virt_helper(gva_t addr, void *val, unsigned int bytes,

while (bytes) {
gpa_t gpa = mmu->gva_to_gpa(vcpu, mmu, addr, access,
- PWALK_SET_ALL, exception);
+ PWALK_SET_ALL, exception, NULL);
unsigned offset = addr & (PAGE_SIZE-1);
unsigned toread = min(bytes, (unsigned)PAGE_SIZE - offset);
int ret;
@@ -7652,7 +7654,8 @@ static int kvm_fetch_guest_virt(struct x86_emulate_ctxt *ctxt,

/* Inline kvm_read_guest_virt_helper for speed. */
gpa_t gpa = mmu->gva_to_gpa(vcpu, mmu, addr, access | PFERR_FETCH_MASK,
- PWALK_SET_ALL, exception);
+ PWALK_SET_ALL,
+ exception, NULL);
if (unlikely(gpa == INVALID_GPA))
return X86EMUL_PROPAGATE_FAULT;

@@ -7710,7 +7713,7 @@ static int kvm_write_guest_virt_helper(gva_t addr, void *val, unsigned int bytes

while (bytes) {
gpa_t gpa = mmu->gva_to_gpa(vcpu, mmu, addr, access,
- PWALK_SET_ALL, exception);
+ PWALK_SET_ALL, exception, NULL);
unsigned offset = addr & (PAGE_SIZE-1);
unsigned towrite = min(bytes, (unsigned)PAGE_SIZE - offset);
int ret;
@@ -7830,7 +7833,7 @@ static int vcpu_mmio_gva_to_gpa(struct kvm_vcpu *vcpu, unsigned long gva,
return 1;
}

- *gpa = mmu->gva_to_gpa(vcpu, mmu, gva, access, PWALK_SET_ALL, exception);
+ *gpa = mmu->gva_to_gpa(vcpu, mmu, gva, access, PWALK_SET_ALL, exception, NULL);

if (*gpa == INVALID_GPA)
return -1;
@@ -13651,7 +13654,7 @@ void kvm_fixup_and_inject_pf_error(struct kvm_vcpu *vcpu, gva_t gva, u16 error_c

if (!(error_code & PFERR_PRESENT_MASK) ||
mmu->gva_to_gpa(vcpu, mmu, gva, access, PWALK_SET_ALL,
- &fault) != INVALID_GPA) {
+ &fault, NULL) != INVALID_GPA) {
/*
* If vcpu->arch.walk_mmu->gva_to_gpa succeeded, the page
* tables probably do not match the TLB. Just proceed
--
2.40.1

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