[PATCH 09/29] KVM: MMU: Track page fault data in struct vcpu

From: Joerg Roedel
Date: Fri Sep 10 2010 - 11:35:56 EST

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This patch introduces a struct with two new fields in
vcpu_arch for x86:

* fault.address
* fault.error_code

This will be used to correctly propagate page faults back
into the guest when we could have either an ordinary page
fault or a nested page fault. In the case of a nested page
fault the fault-address is different from the original
address that should be walked. So we need to keep track
about the real fault-address.

Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
---
arch/x86/include/asm/kvm_emulate.h | 1 -
arch/x86/include/asm/kvm_host.h | 17 ++++++++++++-----
arch/x86/kvm/emulate.c | 30 ++++++++++++++----------------
arch/x86/kvm/mmu.c | 6 ++----
arch/x86/kvm/paging_tmpl.h | 6 +++++-
arch/x86/kvm/x86.c | 9 +++++----
6 files changed, 38 insertions(+), 31 deletions(-)

diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index 1bf1140..5187dd8 100644
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -229,7 +229,6 @@ struct x86_emulate_ctxt {
int exception; /* exception that happens during emulation or -1 */
u32 error_code; /* error code for exception */
bool error_code_valid;
- unsigned long cr2; /* faulted address in case of #PF */

/* decode cache */
struct decode_cache decode;
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3fefcd8..235023e 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -239,9 +239,7 @@ struct kvm_mmu {
void (*set_cr3)(struct kvm_vcpu *vcpu, unsigned long root);
unsigned long (*get_cr3)(struct kvm_vcpu *vcpu);
int (*page_fault)(struct kvm_vcpu *vcpu, gva_t gva, u32 err);
- void (*inject_page_fault)(struct kvm_vcpu *vcpu,
- unsigned long addr,
- u32 error_code);
+ void (*inject_page_fault)(struct kvm_vcpu *vcpu);
void (*free)(struct kvm_vcpu *vcpu);
gpa_t (*gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t gva, u32 access,
u32 *error);
@@ -288,6 +286,16 @@ struct kvm_vcpu_arch {
bool tpr_access_reporting;

struct kvm_mmu mmu;
+
+ /*
+ * This struct is filled with the necessary information to propagate a
+ * page fault into the guest
+ */
+ struct {
+ u64 address;
+ unsigned error_code;
+ } fault;
+
/* only needed in kvm_pv_mmu_op() path, but it's hot so
* put it here to avoid allocation */
struct kvm_pv_mmu_op_buffer mmu_op_buffer;
@@ -624,8 +632,7 @@ void kvm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr);
void kvm_queue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code);
void kvm_requeue_exception(struct kvm_vcpu *vcpu, unsigned nr);
void kvm_requeue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code);
-void kvm_inject_page_fault(struct kvm_vcpu *vcpu, unsigned long cr2,
- u32 error_code);
+void kvm_inject_page_fault(struct kvm_vcpu *vcpu);
bool kvm_require_cpl(struct kvm_vcpu *vcpu, int required_cpl);

int kvm_pic_set_irq(void *opaque, int irq, int level);
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 27d2c22..2b08b78 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -487,11 +487,9 @@ static void emulate_gp(struct x86_emulate_ctxt *ctxt, int err)
emulate_exception(ctxt, GP_VECTOR, err, true);
}

-static void emulate_pf(struct x86_emulate_ctxt *ctxt, unsigned long addr,
- int err)
+static void emulate_pf(struct x86_emulate_ctxt *ctxt)
{
- ctxt->cr2 = addr;
- emulate_exception(ctxt, PF_VECTOR, err, true);
+ emulate_exception(ctxt, PF_VECTOR, 0, true);
}

static void emulate_ud(struct x86_emulate_ctxt *ctxt)
@@ -834,7 +832,7 @@ static int read_emulated(struct x86_emulate_ctxt *ctxt,
rc = ops->read_emulated(addr, mc->data + mc->end, n, &err,
ctxt->vcpu);
if (rc == X86EMUL_PROPAGATE_FAULT)
- emulate_pf(ctxt, addr, err);
+ emulate_pf(ctxt);
if (rc != X86EMUL_CONTINUE)
return rc;
mc->end += n;
@@ -921,7 +919,7 @@ static int read_segment_descriptor(struct x86_emulate_ctxt *ctxt,
addr = dt.address + index * 8;
ret = ops->read_std(addr, desc, sizeof *desc, ctxt->vcpu, &err);
if (ret == X86EMUL_PROPAGATE_FAULT)
- emulate_pf(ctxt, addr, err);
+ emulate_pf(ctxt);

return ret;
}
@@ -947,7 +945,7 @@ static int write_segment_descriptor(struct x86_emulate_ctxt *ctxt,
addr = dt.address + index * 8;
ret = ops->write_std(addr, desc, sizeof *desc, ctxt->vcpu, &err);
if (ret == X86EMUL_PROPAGATE_FAULT)
- emulate_pf(ctxt, addr, err);
+ emulate_pf(ctxt);

return ret;
}
@@ -1117,7 +1115,7 @@ static inline int writeback(struct x86_emulate_ctxt *ctxt,
&err,
ctxt->vcpu);
if (rc == X86EMUL_PROPAGATE_FAULT)
- emulate_pf(ctxt, c->dst.addr.mem, err);
+ emulate_pf(ctxt);
if (rc != X86EMUL_CONTINUE)
return rc;
break;
@@ -1939,7 +1937,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
&err);
if (ret == X86EMUL_PROPAGATE_FAULT) {
/* FIXME: need to provide precise fault address */
- emulate_pf(ctxt, old_tss_base, err);
+ emulate_pf(ctxt);
return ret;
}

@@ -1949,7 +1947,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
&err);
if (ret == X86EMUL_PROPAGATE_FAULT) {
/* FIXME: need to provide precise fault address */
- emulate_pf(ctxt, old_tss_base, err);
+ emulate_pf(ctxt);
return ret;
}

@@ -1957,7 +1955,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
&err);
if (ret == X86EMUL_PROPAGATE_FAULT) {
/* FIXME: need to provide precise fault address */
- emulate_pf(ctxt, new_tss_base, err);
+ emulate_pf(ctxt);
return ret;
}

@@ -1970,7 +1968,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
ctxt->vcpu, &err);
if (ret == X86EMUL_PROPAGATE_FAULT) {
/* FIXME: need to provide precise fault address */
- emulate_pf(ctxt, new_tss_base, err);
+ emulate_pf(ctxt);
return ret;
}
}
@@ -2081,7 +2079,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
&err);
if (ret == X86EMUL_PROPAGATE_FAULT) {
/* FIXME: need to provide precise fault address */
- emulate_pf(ctxt, old_tss_base, err);
+ emulate_pf(ctxt);
return ret;
}

@@ -2091,7 +2089,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
&err);
if (ret == X86EMUL_PROPAGATE_FAULT) {
/* FIXME: need to provide precise fault address */
- emulate_pf(ctxt, old_tss_base, err);
+ emulate_pf(ctxt);
return ret;
}

@@ -2099,7 +2097,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
&err);
if (ret == X86EMUL_PROPAGATE_FAULT) {
/* FIXME: need to provide precise fault address */
- emulate_pf(ctxt, new_tss_base, err);
+ emulate_pf(ctxt);
return ret;
}

@@ -2112,7 +2110,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
ctxt->vcpu, &err);
if (ret == X86EMUL_PROPAGATE_FAULT) {
/* FIXME: need to provide precise fault address */
- emulate_pf(ctxt, new_tss_base, err);
+ emulate_pf(ctxt);
return ret;
}
}
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 86f7557..9936727 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2566,11 +2566,9 @@ static unsigned long get_cr3(struct kvm_vcpu *vcpu)
return vcpu->arch.cr3;
}

-static void inject_page_fault(struct kvm_vcpu *vcpu,
- u64 addr,
- u32 err_code)
+static void inject_page_fault(struct kvm_vcpu *vcpu)
{
- vcpu->arch.mmu.inject_page_fault(vcpu, addr, err_code);
+ vcpu->arch.mmu.inject_page_fault(vcpu);
}

static void paging_free(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 68ee1b7..d07f48a 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -258,6 +258,10 @@ error:
walker->error_code |= PFERR_FETCH_MASK;
if (rsvd_fault)
walker->error_code |= PFERR_RSVD_MASK;
+
+ vcpu->arch.fault.address = addr;
+ vcpu->arch.fault.error_code = walker->error_code;
+
trace_kvm_mmu_walker_error(walker->error_code);
return 0;
}
@@ -521,7 +525,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
*/
if (!r) {
pgprintk("%s: guest page fault\n", __func__);
- inject_page_fault(vcpu, addr, walker.error_code);
+ inject_page_fault(vcpu);
vcpu->arch.last_pt_write_count = 0; /* reset fork detector */
return 0;
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f47db25..57c97a4 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -329,11 +329,12 @@ void kvm_requeue_exception(struct kvm_vcpu *vcpu, unsigned nr)
}
EXPORT_SYMBOL_GPL(kvm_requeue_exception);

-void kvm_inject_page_fault(struct kvm_vcpu *vcpu, unsigned long addr,
- u32 error_code)
+void kvm_inject_page_fault(struct kvm_vcpu *vcpu)
{
+ unsigned error_code = vcpu->arch.fault.error_code;
+
++vcpu->stat.pf_guest;
- vcpu->arch.cr2 = addr;
+ vcpu->arch.cr2 = vcpu->arch.fault.address;
kvm_queue_exception_e(vcpu, PF_VECTOR, error_code);
}

@@ -4066,7 +4067,7 @@ static void inject_emulated_exception(struct kvm_vcpu *vcpu)
{
struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
if (ctxt->exception == PF_VECTOR)
- kvm_inject_page_fault(vcpu, ctxt->cr2, ctxt->error_code);
+ kvm_inject_page_fault(vcpu);
else if (ctxt->error_code_valid)
kvm_queue_exception_e(vcpu, ctxt->exception, ctxt->error_code);
else
--
1.7.0.4

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Next message: Joerg Roedel: "[PATCH 27/29] KVM: SVM: Expect two more candiates for exit_int_info"
Previous message: Joerg Roedel: "[PATCH 07/29] KVM: MMU: Introduce kvm_init_shadow_mmu helper function"
In reply to: Joerg Roedel: "[PATCH 07/29] KVM: MMU: Introduce kvm_init_shadow_mmu helper function"
Next in thread: Joerg Roedel: "[PATCH 27/29] KVM: SVM: Expect two more candiates for exit_int_info"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]