[COMMIT master] KVM: x86: ignore access permissions for hypercall patching
From: Marcelo Tosatti mtosa...@redhat.com
Ignore access permissions while patching hypercall instructions.
Otherwise KVM injects a page fault when trying to patch vmcall
on read-only text regions:
Freeing initrd memory: 8843k freed
Freeing unused kernel memory: 660k freed
Write protecting the kernel text: 4780k
Write protecting the kernel read-only data: 1912k
BUG: unable to handle kernel paging request at c01292e3
IP: [c01292e3] kvm_leave_lazy_mmu+0x43/0x70
*pde = 00910067 *pte = 00129161
Oops: 0003 [#1] SMP
CC: sta...@kernel.org
Reported-and-Tested-by: Stefan Bader stefan.ba...@canonical.com
Signed-off-by: Marcelo Tosatti mtosa...@redhat.com
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index bcf52d1..9d02cc7 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3226,12 +3226,17 @@ int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t
gpa,
static int emulator_write_emulated_onepage(unsigned long addr,
const void *val,
unsigned int bytes,
- struct kvm_vcpu *vcpu)
+ struct kvm_vcpu *vcpu,
+ bool guest_initiated)
{
gpa_t gpa;
u32 error_code;
- gpa = kvm_mmu_gva_to_gpa_write(vcpu, addr, error_code);
+
+ if (guest_initiated)
+ gpa = kvm_mmu_gva_to_gpa_write(vcpu, addr, error_code);
+ else
+ gpa = kvm_mmu_gva_to_gpa_system(vcpu, addr, error_code);
if (gpa == UNMAPPED_GVA) {
kvm_inject_page_fault(vcpu, addr, error_code);
@@ -3262,24 +3267,35 @@ mmio:
return X86EMUL_CONTINUE;
}
-int emulator_write_emulated(unsigned long addr,
+int __emulator_write_emulated(unsigned long addr,
const void *val,
unsigned int bytes,
- struct kvm_vcpu *vcpu)
+ struct kvm_vcpu *vcpu,
+ bool guest_initiated)
{
/* Crossing a page boundary? */
if (((addr + bytes - 1) ^ addr) PAGE_MASK) {
int rc, now;
now = -addr ~PAGE_MASK;
- rc = emulator_write_emulated_onepage(addr, val, now, vcpu);
+ rc = emulator_write_emulated_onepage(addr, val, now, vcpu,
+guest_initiated);
if (rc != X86EMUL_CONTINUE)
return rc;
addr += now;
val += now;
bytes -= now;
}
- return emulator_write_emulated_onepage(addr, val, bytes, vcpu);
+ return emulator_write_emulated_onepage(addr, val, bytes, vcpu,
+ guest_initiated);
+}
+
+int emulator_write_emulated(unsigned long addr,
+ const void *val,
+ unsigned int bytes,
+ struct kvm_vcpu *vcpu)
+{
+ return __emulator_write_emulated(addr, val, bytes, vcpu, true);
}
EXPORT_SYMBOL_GPL(emulator_write_emulated);
@@ -3970,7 +3986,7 @@ int kvm_fix_hypercall(struct kvm_vcpu *vcpu)
kvm_x86_ops-patch_hypercall(vcpu, instruction);
- return emulator_write_emulated(rip, instruction, 3, vcpu);
+ return __emulator_write_emulated(rip, instruction, 3, vcpu, false);
}
static u64 mk_cr_64(u64 curr_cr, u32 new_val)
--
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[COMMIT master] Revert KVM: x86: ignore access permissions for hypercall patching
From: Marcelo Tosatti mtosa...@redhat.com
Its safer to disable the only problematic user of hypercall patching,
pvmmu.
Signed-off-by: Marcelo Tosatti mtosa...@redhat.com
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 68e8c89..bb9a24a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3243,17 +3243,12 @@ static int emulator_write_emulated_onepage(unsigned
long addr,
const void *val,
unsigned int bytes,
struct kvm_vcpu *vcpu,
- bool guest_initiated,
bool mmu_only)
{
gpa_t gpa;
u32 error_code;
-
- if (guest_initiated)
- gpa = kvm_mmu_gva_to_gpa_write(vcpu, addr, error_code);
- else
- gpa = kvm_mmu_gva_to_gpa_system(vcpu, addr, error_code);
+ gpa = kvm_mmu_gva_to_gpa_write(vcpu, addr, error_code);
if (gpa == UNMAPPED_GVA) {
kvm_inject_page_fault(vcpu, addr, error_code);
@@ -3292,7 +3287,6 @@ int __emulator_write_emulated(unsigned long addr,
const void *val,
unsigned int bytes,
struct kvm_vcpu *vcpu,
- bool guest_initiated,
bool mmu_only)
{
/* Crossing a page boundary? */
@@ -3301,7 +3295,7 @@ int __emulator_write_emulated(unsigned long addr,
now = -addr ~PAGE_MASK;
rc = emulator_write_emulated_onepage(addr, val, now, vcpu,
-guest_initiated, mmu_only);
+mmu_only);
if (rc != X86EMUL_CONTINUE)
return rc;
addr += now;
@@ -3309,7 +3303,7 @@ int __emulator_write_emulated(unsigned long addr,
bytes -= now;
}
return emulator_write_emulated_onepage(addr, val, bytes, vcpu,
- guest_initiated, mmu_only);
+ mmu_only);
}
int emulator_write_emulated(unsigned long addr,
@@ -3317,7 +3311,7 @@ int emulator_write_emulated(unsigned long addr,
unsigned int bytes,
struct kvm_vcpu *vcpu)
{
- return __emulator_write_emulated(addr, val, bytes, vcpu, true, false);
+ return __emulator_write_emulated(addr, val, bytes, vcpu, false);
}
EXPORT_SYMBOL_GPL(emulator_write_emulated);
@@ -3381,7 +3375,7 @@ static int emulator_cmpxchg_emulated(unsigned long addr,
if (!exchanged)
return X86EMUL_CMPXCHG_FAILED;
- return __emulator_write_emulated(addr, new, bytes, vcpu, true, true);
+ return __emulator_write_emulated(addr, new, bytes, vcpu, true);
emul_write:
printk_once(KERN_WARNING kvm: emulating exchange as write\n);
@@ -4083,8 +4077,7 @@ int kvm_fix_hypercall(struct kvm_vcpu *vcpu)
kvm_x86_ops-patch_hypercall(vcpu, instruction);
- return __emulator_write_emulated(rip, instruction, 3, vcpu,
-false, false);
+ return __emulator_write_emulated(rip, instruction, 3, vcpu, false);
}
void realmode_lgdt(struct kvm_vcpu *vcpu, u16 limit, unsigned long base)
--
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KVM: x86: ignore access permissions for hypercall patching
Ignore access permissions while patching hypercall instructions.
Otherwise KVM injects a page fault when trying to patch vmcall
on read-only text regions:
Freeing initrd memory: 8843k freed
Freeing unused kernel memory: 660k freed
Write protecting the kernel text: 4780k
Write protecting the kernel read-only data: 1912k
BUG: unable to handle kernel paging request at c01292e3
IP: [c01292e3] kvm_leave_lazy_mmu+0x43/0x70
*pde = 00910067 *pte = 00129161
Oops: 0003 [#1] SMP
CC: sta...@kernel.org
Reported-by: Stefan Bader stefan.ba...@canonical.com
Signed-off-by: Marcelo Tosatti mtosa...@redhat.com
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 703f637..bf5c83f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3253,12 +3253,17 @@ int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t
gpa,
static int emulator_write_emulated_onepage(unsigned long addr,
const void *val,
unsigned int bytes,
- struct kvm_vcpu *vcpu)
+ struct kvm_vcpu *vcpu,
+ bool guest_initiated)
{
gpa_t gpa;
u32 error_code;
- gpa = kvm_mmu_gva_to_gpa_write(vcpu, addr, error_code);
+
+ if (guest_initiated)
+ gpa = kvm_mmu_gva_to_gpa_write(vcpu, addr, error_code);
+ else
+ gpa = kvm_mmu_gva_to_gpa_system(vcpu, addr, error_code);
if (gpa == UNMAPPED_GVA) {
kvm_inject_page_fault(vcpu, addr, error_code);
@@ -3289,24 +3294,35 @@ mmio:
return X86EMUL_CONTINUE;
}
-int emulator_write_emulated(unsigned long addr,
+int __emulator_write_emulated(unsigned long addr,
const void *val,
unsigned int bytes,
- struct kvm_vcpu *vcpu)
+ struct kvm_vcpu *vcpu,
+ bool guest_initiated)
{
/* Crossing a page boundary? */
if (((addr + bytes - 1) ^ addr) PAGE_MASK) {
int rc, now;
now = -addr ~PAGE_MASK;
- rc = emulator_write_emulated_onepage(addr, val, now, vcpu);
+ rc = emulator_write_emulated_onepage(addr, val, now, vcpu,
+guest_initiated);
if (rc != X86EMUL_CONTINUE)
return rc;
addr += now;
val += now;
bytes -= now;
}
- return emulator_write_emulated_onepage(addr, val, bytes, vcpu);
+ return emulator_write_emulated_onepage(addr, val, bytes, vcpu,
+ guest_initiated);
+}
+
+int emulator_write_emulated(unsigned long addr,
+ const void *val,
+ unsigned int bytes,
+ struct kvm_vcpu *vcpu)
+{
+ return __emulator_write_emulated(addr, val, bytes, vcpu, true);
}
EXPORT_SYMBOL_GPL(emulator_write_emulated);
@@ -3997,7 +4013,7 @@ int kvm_fix_hypercall(struct kvm_vcpu *vcpu)
kvm_x86_ops-patch_hypercall(vcpu, instruction);
- return emulator_write_emulated(rip, instruction, 3, vcpu);
+ return __emulator_write_emulated(rip, instruction, 3, vcpu, false);
}
static u64 mk_cr_64(u64 curr_cr, u32 new_val)
--
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Re: KVM: x86: ignore access permissions for hypercall patching
With this patch applied on top, I was able to boot my guest on a AMD host
system.
Marcelo Tosatti wrote:
Ignore access permissions while patching hypercall instructions.
Otherwise KVM injects a page fault when trying to patch vmcall
on read-only text regions:
Freeing initrd memory: 8843k freed
Freeing unused kernel memory: 660k freed
Write protecting the kernel text: 4780k
Write protecting the kernel read-only data: 1912k
BUG: unable to handle kernel paging request at c01292e3
IP: [c01292e3] kvm_leave_lazy_mmu+0x43/0x70
*pde = 00910067 *pte = 00129161
Oops: 0003 [#1] SMP
CC: sta...@kernel.org
Reported-by: Stefan Bader stefan.ba...@canonical.com
Signed-off-by: Marcelo Tosatti mtosa...@redhat.com
Tested-by: Stefan Bader stefan.ba...@canonical.com
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 703f637..bf5c83f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3253,12 +3253,17 @@ int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t
gpa,
static int emulator_write_emulated_onepage(unsigned long addr,
const void *val,
unsigned int bytes,
-struct kvm_vcpu *vcpu)
+struct kvm_vcpu *vcpu,
+bool guest_initiated)
{
gpa_t gpa;
u32 error_code;
- gpa = kvm_mmu_gva_to_gpa_write(vcpu, addr, error_code);
+
+ if (guest_initiated)
+ gpa = kvm_mmu_gva_to_gpa_write(vcpu, addr, error_code);
+ else
+ gpa = kvm_mmu_gva_to_gpa_system(vcpu, addr, error_code);
if (gpa == UNMAPPED_GVA) {
kvm_inject_page_fault(vcpu, addr, error_code);
@@ -3289,24 +3294,35 @@ mmio:
return X86EMUL_CONTINUE;
}
-int emulator_write_emulated(unsigned long addr,
+int __emulator_write_emulated(unsigned long addr,
const void *val,
unsigned int bytes,
-struct kvm_vcpu *vcpu)
+struct kvm_vcpu *vcpu,
+bool guest_initiated)
{
/* Crossing a page boundary? */
if (((addr + bytes - 1) ^ addr) PAGE_MASK) {
int rc, now;
now = -addr ~PAGE_MASK;
- rc = emulator_write_emulated_onepage(addr, val, now, vcpu);
+ rc = emulator_write_emulated_onepage(addr, val, now, vcpu,
+ guest_initiated);
if (rc != X86EMUL_CONTINUE)
return rc;
addr += now;
val += now;
bytes -= now;
}
- return emulator_write_emulated_onepage(addr, val, bytes, vcpu);
+ return emulator_write_emulated_onepage(addr, val, bytes, vcpu,
+guest_initiated);
+}
+
+int emulator_write_emulated(unsigned long addr,
+const void *val,
+unsigned int bytes,
+struct kvm_vcpu *vcpu)
+{
+ return __emulator_write_emulated(addr, val, bytes, vcpu, true);
}
EXPORT_SYMBOL_GPL(emulator_write_emulated);
@@ -3997,7 +4013,7 @@ int kvm_fix_hypercall(struct kvm_vcpu *vcpu)
kvm_x86_ops-patch_hypercall(vcpu, instruction);
- return emulator_write_emulated(rip, instruction, 3, vcpu);
+ return __emulator_write_emulated(rip, instruction, 3, vcpu, false);
}
static u64 mk_cr_64(u64 curr_cr, u32 new_val)
--
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Re: KVM: x86: ignore access permissions for hypercall patching
On Thu, Mar 11, 2010 at 06:16:05PM -0300, Marcelo Tosatti wrote:
Ignore access permissions while patching hypercall instructions.
Otherwise KVM injects a page fault when trying to patch vmcall
on read-only text regions:
Freeing initrd memory: 8843k freed
Freeing unused kernel memory: 660k freed
Write protecting the kernel text: 4780k
Write protecting the kernel read-only data: 1912k
BUG: unable to handle kernel paging request at c01292e3
IP: [c01292e3] kvm_leave_lazy_mmu+0x43/0x70
*pde = 00910067 *pte = 00129161
Oops: 0003 [#1] SMP
CC: sta...@kernel.org
Reported-by: Stefan Bader stefan.ba...@canonical.com
Signed-off-by: Marcelo Tosatti mtosa...@redhat.com
My emulator patch series introduce kvm_write_guest_virt_system(). May be
used it here (only compile tested).
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3753c11..9833c25 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3157,14 +3157,18 @@ static int kvm_read_guest_virt_system(gva_t addr, void
*val, unsigned int bytes,
return kvm_read_guest_virt_helper(addr, val, bytes, vcpu, 0, error);
}
-static int kvm_write_guest_virt(gva_t addr, void *val, unsigned int bytes,
- struct kvm_vcpu *vcpu, u32 *error)
+static int kvm_write_guest_virt_helper(gva_t addr, void *val,
+ unsigned int bytes,
+ struct kvm_vcpu *vcpu, u32 access,
+ u32 *error)
{
void *data = val;
int r = X86EMUL_CONTINUE;
+ access |= PFERR_WRITE_MASK;
+
while (bytes) {
- gpa_t gpa = kvm_mmu_gva_to_gpa_write(vcpu, addr, error);
+ gpa_t gpa = vcpu-arch.mmu.gva_to_gpa(vcpu, addr, access,
error);
unsigned offset = addr (PAGE_SIZE-1);
unsigned towrite = min(bytes, (unsigned)PAGE_SIZE - offset);
int ret;
@@ -3187,6 +3191,19 @@ out:
return r;
}
+static int kvm_write_guest_virt(gva_t addr, void *val, unsigned int bytes,
+ struct kvm_vcpu *vcpu, u32 *error)
+{
+ u32 access = (kvm_x86_ops-get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
+ return kvm_write_guest_virt_helper(addr, val, bytes, vcpu, access,
error);
+}
+
+static int kvm_write_guest_virt_system(gva_t addr, void *val,
+ unsigned int bytes,
+ struct kvm_vcpu *vcpu, u32 *error)
+{
+ return kvm_write_guest_virt_helper(addr, val, bytes, vcpu, 0, error);
+}
static int emulator_read_emulated(unsigned long addr,
void *val,
@@ -3997,7 +4014,7 @@ int kvm_fix_hypercall(struct kvm_vcpu *vcpu)
kvm_x86_ops-patch_hypercall(vcpu, instruction);
- return emulator_write_emulated(rip, instruction, 3, vcpu);
+ return kvm_write_guest_virt_system(rip, instruction, 3, vcpu, NULL);
}
static u64 mk_cr_64(u64 curr_cr, u32 new_val)
--
Gleb.
--
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Re: KVM: x86: ignore access permissions for hypercall patching
On Fri, Mar 12, 2010 at 07:56:00AM +0200, Gleb Natapov wrote: On Thu, Mar 11, 2010 at 06:16:05PM -0300, Marcelo Tosatti wrote: Ignore access permissions while patching hypercall instructions. Otherwise KVM injects a page fault when trying to patch vmcall on read-only text regions: Freeing initrd memory: 8843k freed Freeing unused kernel memory: 660k freed Write protecting the kernel text: 4780k Write protecting the kernel read-only data: 1912k BUG: unable to handle kernel paging request at c01292e3 IP: [c01292e3] kvm_leave_lazy_mmu+0x43/0x70 *pde = 00910067 *pte = 00129161 Oops: 0003 [#1] SMP CC: sta...@kernel.org Reported-by: Stefan Bader stefan.ba...@canonical.com Signed-off-by: Marcelo Tosatti mtosa...@redhat.com My emulator patch series introduce kvm_write_guest_virt_system(). May be used it here (only compile tested). Ignore that, it will not work. -- Gleb. -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
