[PATCH V2 1/5] KVM: X86: Change the type of access u32 to u64

From: Lai Jiangshan
Date: Fri Mar 11 2022 - 02:03:26 EST

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From: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx>

Change the type of access u32 to u64 for FNAME(walk_addr) and
->gva_to_gpa().

The kinds of accesses are usually combinations of UWX, and VMX/SVM's
nested paging adds a new factor of access: is it an access for a guest
page table or for a final guest physical address.

And SMAP relies a factor for supervisor access: explicit or implicit.

So @access in FNAME(walk_addr) and ->gva_to_gpa() is better to include
all these information to do the walk.

Although @access(u32) has enough bits to encode all the kinds, this
patch extends it to u64:
o Extra bits will be in the higher 32 bits, so that we can
easily obtain the traditional access mode (UWX) by converting
it to u32.
o Reuse the value for the access kind defined by SVM's nested
paging (PFERR_GUEST_FINAL_MASK and PFERR_GUEST_PAGE_MASK) as
@error_code in kvm_handle_page_fault().

Signed-off-by: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/mmu.h | 8 +++++---
arch/x86/kvm/mmu/mmu.c | 2 +-
arch/x86/kvm/mmu/paging_tmpl.h | 8 ++++----
arch/x86/kvm/x86.c | 24 ++++++++++++------------
5 files changed, 23 insertions(+), 21 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index c45ab8b5c37f..edffcf7f9c2d 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -429,7 +429,7 @@ struct kvm_mmu {
void (*inject_page_fault)(struct kvm_vcpu *vcpu,
struct x86_exception *fault);
gpa_t (*gva_to_gpa)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
- gpa_t gva_or_gpa, u32 access,
+ gpa_t gva_or_gpa, u64 access,
struct x86_exception *exception);
int (*sync_page)(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp);
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index bf8dbc4bb12a..74efeaefa8f8 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -214,8 +214,10 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
*/
static inline u8 permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
unsigned pte_access, unsigned pte_pkey,
- unsigned pfec)
+ u64 access)
{
+ /* strip nested paging fault error codes */
+ unsigned int pfec = access;
int cpl = static_call(kvm_x86_get_cpl)(vcpu);
unsigned long rflags = static_call(kvm_x86_get_rflags)(vcpu);

@@ -317,12 +319,12 @@ static inline void kvm_update_page_stats(struct kvm *kvm, int level, int count)
atomic64_add(count, &kvm->stat.pages[level - 1]);
}

-gpa_t translate_nested_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u32 access,
+gpa_t translate_nested_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u64 access,
struct x86_exception *exception);

static inline gpa_t kvm_translate_gpa(struct kvm_vcpu *vcpu,
struct kvm_mmu *mmu,
- gpa_t gpa, u32 access,
+ gpa_t gpa, u64 access,
struct x86_exception *exception)
{
if (mmu != &vcpu->arch.nested_mmu)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index bd3625a875ef..c12133c3cf00 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3703,7 +3703,7 @@ 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, u32 access,
+ gpa_t vaddr, u64 access,
struct x86_exception *exception)
{
if (exception)
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 252c77805eb9..8621188b46df 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -339,7 +339,7 @@ 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, u32 access)
+ gpa_t addr, u64 access)
{
int ret;
pt_element_t pte;
@@ -347,7 +347,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
gfn_t table_gfn;
u64 pt_access, pte_access;
unsigned index, accessed_dirty, pte_pkey;
- unsigned nested_access;
+ u64 nested_access;
gpa_t pte_gpa;
bool have_ad;
int offset;
@@ -540,7 +540,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
}

static int FNAME(walk_addr)(struct guest_walker *walker,
- struct kvm_vcpu *vcpu, gpa_t addr, u32 access)
+ struct kvm_vcpu *vcpu, gpa_t addr, u64 access)
{
return FNAME(walk_addr_generic)(walker, vcpu, vcpu->arch.mmu, addr,
access);
@@ -988,7 +988,7 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva, hpa_t root_hpa)

/* 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, u32 access,
+ gpa_t addr, u64 access,
struct x86_exception *exception)
{
struct guest_walker walker;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cf17af4d6904..c85e48dc8310 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6705,7 +6705,7 @@ void kvm_get_segment(struct kvm_vcpu *vcpu,
static_call(kvm_x86_get_segment)(vcpu, var, seg);
}

-gpa_t translate_nested_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u32 access,
+gpa_t translate_nested_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u64 access,
struct x86_exception *exception)
{
struct kvm_mmu *mmu = vcpu->arch.mmu;
@@ -6725,7 +6725,7 @@ gpa_t kvm_mmu_gva_to_gpa_read(struct kvm_vcpu *vcpu, gva_t gva,
{
struct kvm_mmu *mmu = vcpu->arch.walk_mmu;

- u32 access = (static_call(kvm_x86_get_cpl)(vcpu) == 3) ? PFERR_USER_MASK : 0;
+ u64 access = (static_call(kvm_x86_get_cpl)(vcpu) == 3) ? PFERR_USER_MASK : 0;
return mmu->gva_to_gpa(vcpu, mmu, gva, access, exception);
}
EXPORT_SYMBOL_GPL(kvm_mmu_gva_to_gpa_read);
@@ -6735,7 +6735,7 @@ EXPORT_SYMBOL_GPL(kvm_mmu_gva_to_gpa_read);
{
struct kvm_mmu *mmu = vcpu->arch.walk_mmu;

- u32 access = (static_call(kvm_x86_get_cpl)(vcpu) == 3) ? PFERR_USER_MASK : 0;
+ u64 access = (static_call(kvm_x86_get_cpl)(vcpu) == 3) ? PFERR_USER_MASK : 0;
access |= PFERR_FETCH_MASK;
return mmu->gva_to_gpa(vcpu, mmu, gva, access, exception);
}
@@ -6745,7 +6745,7 @@ gpa_t kvm_mmu_gva_to_gpa_write(struct kvm_vcpu *vcpu, gva_t gva,
{
struct kvm_mmu *mmu = vcpu->arch.walk_mmu;

- u32 access = (static_call(kvm_x86_get_cpl)(vcpu) == 3) ? PFERR_USER_MASK : 0;
+ u64 access = (static_call(kvm_x86_get_cpl)(vcpu) == 3) ? PFERR_USER_MASK : 0;
access |= PFERR_WRITE_MASK;
return mmu->gva_to_gpa(vcpu, mmu, gva, access, exception);
}
@@ -6761,7 +6761,7 @@ gpa_t kvm_mmu_gva_to_gpa_system(struct kvm_vcpu *vcpu, gva_t gva,
}

static int kvm_read_guest_virt_helper(gva_t addr, void *val, unsigned int bytes,
- struct kvm_vcpu *vcpu, u32 access,
+ struct kvm_vcpu *vcpu, u64 access,
struct x86_exception *exception)
{
struct kvm_mmu *mmu = vcpu->arch.walk_mmu;
@@ -6798,7 +6798,7 @@ static int kvm_fetch_guest_virt(struct x86_emulate_ctxt *ctxt,
{
struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
struct kvm_mmu *mmu = vcpu->arch.walk_mmu;
- u32 access = (static_call(kvm_x86_get_cpl)(vcpu) == 3) ? PFERR_USER_MASK : 0;
+ u64 access = (static_call(kvm_x86_get_cpl)(vcpu) == 3) ? PFERR_USER_MASK : 0;
unsigned offset;
int ret;

@@ -6823,7 +6823,7 @@ int kvm_read_guest_virt(struct kvm_vcpu *vcpu,
gva_t addr, void *val, unsigned int bytes,
struct x86_exception *exception)
{
- u32 access = (static_call(kvm_x86_get_cpl)(vcpu) == 3) ? PFERR_USER_MASK : 0;
+ u64 access = (static_call(kvm_x86_get_cpl)(vcpu) == 3) ? PFERR_USER_MASK : 0;

/*
* FIXME: this should call handle_emulation_failure if X86EMUL_IO_NEEDED
@@ -6842,7 +6842,7 @@ static int emulator_read_std(struct x86_emulate_ctxt *ctxt,
struct x86_exception *exception, bool system)
{
struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
- u32 access = 0;
+ u64 access = 0;

if (!system && static_call(kvm_x86_get_cpl)(vcpu) == 3)
access |= PFERR_USER_MASK;
@@ -6860,7 +6860,7 @@ static int kvm_read_guest_phys_system(struct x86_emulate_ctxt *ctxt,
}

static int kvm_write_guest_virt_helper(gva_t addr, void *val, unsigned int bytes,
- struct kvm_vcpu *vcpu, u32 access,
+ struct kvm_vcpu *vcpu, u64 access,
struct x86_exception *exception)
{
struct kvm_mmu *mmu = vcpu->arch.walk_mmu;
@@ -6894,7 +6894,7 @@ static int emulator_write_std(struct x86_emulate_ctxt *ctxt, gva_t addr, void *v
bool system)
{
struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
- u32 access = PFERR_WRITE_MASK;
+ u64 access = PFERR_WRITE_MASK;

if (!system && static_call(kvm_x86_get_cpl)(vcpu) == 3)
access |= PFERR_USER_MASK;
@@ -6963,7 +6963,7 @@ static int vcpu_mmio_gva_to_gpa(struct kvm_vcpu *vcpu, unsigned long gva,
bool write)
{
struct kvm_mmu *mmu = vcpu->arch.walk_mmu;
- u32 access = ((static_call(kvm_x86_get_cpl)(vcpu) == 3) ? PFERR_USER_MASK : 0)
+ u64 access = ((static_call(kvm_x86_get_cpl)(vcpu) == 3) ? PFERR_USER_MASK : 0)
| (write ? PFERR_WRITE_MASK : 0);

/*
@@ -12558,7 +12558,7 @@ void kvm_fixup_and_inject_pf_error(struct kvm_vcpu *vcpu, gva_t gva, u16 error_c
{
struct kvm_mmu *mmu = vcpu->arch.walk_mmu;
struct x86_exception fault;
- u32 access = error_code &
+ u64 access = error_code &
(PFERR_WRITE_MASK | PFERR_FETCH_MASK | PFERR_USER_MASK);

if (!(error_code & PFERR_PRESENT_MASK) ||
--
2.19.1.6.gb485710b

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