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KVM: x86: Modify struct kvm_nested_state to have explicit fields for data

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Improve the KVM_{GET,SET}_NESTED_STATE structs by detailing the format
of VMX nested state data in a struct.

In order to avoid changing the ioctl values of
KVM_{GET,SET}_NESTED_STATE, there is a need to preserve
sizeof(struct kvm_nested_state). This is done by defining the data
struct as "data.vmx[0]". It was the most elegant way I found to
preserve struct size while still keeping struct readable and easy to
maintain. It does have a misfortunate side-effect that now it has to be
accessed as "data.vmx[0]" rather than just "data.vmx".

Because we are already modifying these structs, I also modified the
following:
* Define the "format" field values as macros.
* Rename vmcs_pa to vmcs12_pa for better readability.

Signed-off-by: Liran Alon <liran.alon@oracle.com>
[Remove SVM stubs, add KVM_STATE_NESTED_VMX_VMCS12_SIZE. - Paolo]
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Liran Alon 2019-06-16 15:03:10 +03:00 committed by Paolo Bonzini
parent 76e3bcdb61
commit 6ca00dfafd
6 changed files with 122 additions and 85 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

46
Documentation/virtual/kvm/api.txt
View File

@ -3857,43 +3857,59 @@ Type: vcpu ioctl
Parameters: struct kvm_nested_state (in/out)
Returns: 0 on success, -1 on error
Errors:
E2BIG: the total state size (including the fixed-size part of struct
kvm_nested_state) exceeds the value of 'size' specified by
E2BIG: the total state size exceeds the value of 'size' specified by
the user; the size required will be written into size.
struct kvm_nested_state {
__u16 flags;
__u16 format;
__u32 size;
union {
struct kvm_vmx_nested_state vmx;
struct kvm_svm_nested_state svm;
struct kvm_vmx_nested_state_hdr vmx;
struct kvm_svm_nested_state_hdr svm;
/* Pad the header to 128 bytes. */
__u8 pad[120];
};
__u8 data[0];
} hdr;
union {
struct kvm_vmx_nested_state_data vmx[0];
struct kvm_svm_nested_state_data svm[0];
} data;
};
#define KVM_STATE_NESTED_GUEST_MODE 0x00000001
#define KVM_STATE_NESTED_RUN_PENDING 0x00000002
#define KVM_STATE_NESTED_EVMCS 0x00000004
#define KVM_STATE_NESTED_SMM_GUEST_MODE 0x00000001
#define KVM_STATE_NESTED_SMM_VMXON 0x00000002
#define KVM_STATE_NESTED_FORMAT_VMX 0
#define KVM_STATE_NESTED_FORMAT_SVM 1
struct kvm_vmx_nested_state {
#define KVM_STATE_NESTED_VMX_VMCS_SIZE 0x1000
#define KVM_STATE_NESTED_VMX_SMM_GUEST_MODE 0x00000001
#define KVM_STATE_NESTED_VMX_SMM_VMXON 0x00000002
struct kvm_vmx_nested_state_hdr {
__u64 vmxon_pa;
__u64 vmcs_pa;
__u64 vmcs12_pa;
struct {
__u16 flags;
} smm;
};
struct kvm_vmx_nested_state_data {
__u8 vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE];
__u8 shadow_vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE];
};
This ioctl copies the vcpu's nested virtualization state from the kernel to
userspace.
The maximum size of the state, including the fixed-size part of struct
kvm_nested_state, can be retrieved by passing KVM_CAP_NESTED_STATE to
the KVM_CHECK_EXTENSION ioctl().
The maximum size of the state can be retrieved by passing KVM_CAP_NESTED_STATE
to the KVM_CHECK_EXTENSION ioctl().
4.115 KVM_SET_NESTED_STATE
@ -3903,8 +3919,8 @@ Type: vcpu ioctl
Parameters: struct kvm_nested_state (in)
Returns: 0 on success, -1 on error
This copies the vcpu's kvm_nested_state struct from userspace to the kernel. For
the definition of struct kvm_nested_state, see KVM_GET_NESTED_STATE.
This copies the vcpu's kvm_nested_state struct from userspace to the kernel.
For the definition of struct kvm_nested_state, see KVM_GET_NESTED_STATE.
4.116 KVM_(UN)REGISTER_COALESCED_MMIO

33
arch/x86/include/uapi/asm/kvm.h
View File

@ -383,6 +383,9 @@ struct kvm_sync_regs {
#define KVM_X86_QUIRK_LAPIC_MMIO_HOLE (1 << 2)
#define KVM_X86_QUIRK_OUT_7E_INC_RIP (1 << 3)
#define KVM_STATE_NESTED_FORMAT_VMX 0
#define KVM_STATE_NESTED_FORMAT_SVM 1 /* unused */
#define KVM_STATE_NESTED_GUEST_MODE 0x00000001
#define KVM_STATE_NESTED_RUN_PENDING 0x00000002
#define KVM_STATE_NESTED_EVMCS 0x00000004
@ -390,9 +393,16 @@ struct kvm_sync_regs {
#define KVM_STATE_NESTED_SMM_GUEST_MODE 0x00000001
#define KVM_STATE_NESTED_SMM_VMXON 0x00000002
struct kvm_vmx_nested_state {
#define KVM_STATE_NESTED_VMX_VMCS_SIZE 0x1000
struct kvm_vmx_nested_state_data {
__u8 vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE];
__u8 shadow_vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE];
};
struct kvm_vmx_nested_state_hdr {
__u64 vmxon_pa;
__u64 vmcs_pa;
__u64 vmcs12_pa;
struct {
__u16 flags;
@ -401,24 +411,25 @@ struct kvm_vmx_nested_state {
/* for KVM_CAP_NESTED_STATE */
struct kvm_nested_state {
/* KVM_STATE_* flags */
__u16 flags;
/* 0 for VMX, 1 for SVM. */
__u16 format;
/* 128 for SVM, 128 + VMCS size for VMX. */
__u32 size;
union {
/* VMXON, VMCS */
struct kvm_vmx_nested_state vmx;
struct kvm_vmx_nested_state_hdr vmx;
/* Pad the header to 128 bytes. */
__u8 pad[120];
};
} hdr;
__u8 data[0];
/*
* Define data region as 0 bytes to preserve backwards-compatability
* to old definition of kvm_nested_state in order to avoid changing
* KVM_{GET,PUT}_NESTED_STATE ioctl values.
*/
union {
struct kvm_vmx_nested_state_data vmx[0];
} data;
};
#endif /* _ASM_X86_KVM_H */

79
arch/x86/kvm/vmx/nested.c
View File

@ -5226,14 +5226,16 @@ static int vmx_get_nested_state(struct kvm_vcpu *vcpu,
struct vmcs12 *vmcs12;
struct kvm_nested_state kvm_state = {
.flags = 0,
.format = 0,
.format = KVM_STATE_NESTED_FORMAT_VMX,
.size = sizeof(kvm_state),
.vmx.vmxon_pa = -1ull,
.vmx.vmcs_pa = -1ull,
.hdr.vmx.vmxon_pa = -1ull,
.hdr.vmx.vmcs12_pa = -1ull,
};
struct kvm_vmx_nested_state_data __user *user_vmx_nested_state =
&user_kvm_nested_state->data.vmx[0];
if (!vcpu)
return kvm_state.size + 2 * VMCS12_SIZE;
return kvm_state.size + sizeof(*user_vmx_nested_state);
vmx = to_vmx(vcpu);
vmcs12 = get_vmcs12(vcpu);
@ -5243,23 +5245,23 @@ static int vmx_get_nested_state(struct kvm_vcpu *vcpu,
if (nested_vmx_allowed(vcpu) &&
(vmx->nested.vmxon || vmx->nested.smm.vmxon)) {
kvm_state.vmx.vmxon_pa = vmx->nested.vmxon_ptr;
kvm_state.vmx.vmcs_pa = vmx->nested.current_vmptr;
kvm_state.hdr.vmx.vmxon_pa = vmx->nested.vmxon_ptr;
kvm_state.hdr.vmx.vmcs12_pa = vmx->nested.current_vmptr;
if (vmx_has_valid_vmcs12(vcpu)) {
kvm_state.size += VMCS12_SIZE;
kvm_state.size += sizeof(user_vmx_nested_state->vmcs12);
if (is_guest_mode(vcpu) &&
nested_cpu_has_shadow_vmcs(vmcs12) &&
vmcs12->vmcs_link_pointer != -1ull)
kvm_state.size += VMCS12_SIZE;
kvm_state.size += sizeof(user_vmx_nested_state->shadow_vmcs12);
}
if (vmx->nested.smm.vmxon)
kvm_state.vmx.smm.flags |= KVM_STATE_NESTED_SMM_VMXON;
kvm_state.hdr.vmx.smm.flags |= KVM_STATE_NESTED_SMM_VMXON;
if (vmx->nested.smm.guest_mode)
kvm_state.vmx.smm.flags |= KVM_STATE_NESTED_SMM_GUEST_MODE;
kvm_state.hdr.vmx.smm.flags |= KVM_STATE_NESTED_SMM_GUEST_MODE;
if (is_guest_mode(vcpu)) {
kvm_state.flags |= KVM_STATE_NESTED_GUEST_MODE;
@ -5294,16 +5296,19 @@ static int vmx_get_nested_state(struct kvm_vcpu *vcpu,
copy_shadow_to_vmcs12(vmx);
}
BUILD_BUG_ON(sizeof(user_vmx_nested_state->vmcs12) < VMCS12_SIZE);
BUILD_BUG_ON(sizeof(user_vmx_nested_state->shadow_vmcs12) < VMCS12_SIZE);
/*
* Copy over the full allocated size of vmcs12 rather than just the size
* of the struct.
*/
if (copy_to_user(user_kvm_nested_state->data, vmcs12, VMCS12_SIZE))
if (copy_to_user(user_vmx_nested_state->vmcs12, vmcs12, VMCS12_SIZE))
return -EFAULT;
if (nested_cpu_has_shadow_vmcs(vmcs12) &&
vmcs12->vmcs_link_pointer != -1ull) {
if (copy_to_user(user_kvm_nested_state->data + VMCS12_SIZE,
if (copy_to_user(user_vmx_nested_state->shadow_vmcs12,
get_shadow_vmcs12(vcpu), VMCS12_SIZE))
return -EFAULT;
}
@ -5331,33 +5336,35 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
struct vcpu_vmx *vmx = to_vmx(vcpu);
struct vmcs12 *vmcs12;
u32 exit_qual;
struct kvm_vmx_nested_state_data __user *user_vmx_nested_state =
&user_kvm_nested_state->data.vmx[0];
int ret;
if (kvm_state->format != 0)
if (kvm_state->format != KVM_STATE_NESTED_FORMAT_VMX)
return -EINVAL;
if (!nested_vmx_allowed(vcpu))
return kvm_state->vmx.vmxon_pa == -1ull ? 0 : -EINVAL;
return kvm_state->hdr.vmx.vmxon_pa == -1ull ? 0 : -EINVAL;
if (kvm_state->vmx.vmxon_pa == -1ull) {
if (kvm_state->vmx.smm.flags)
if (kvm_state->hdr.vmx.vmxon_pa == -1ull) {
if (kvm_state->hdr.vmx.smm.flags)
return -EINVAL;
if (kvm_state->vmx.vmcs_pa != -1ull)
if (kvm_state->hdr.vmx.vmcs12_pa != -1ull)
return -EINVAL;
vmx_leave_nested(vcpu);
return 0;
}
if (!page_address_valid(vcpu, kvm_state->vmx.vmxon_pa))
if (!page_address_valid(vcpu, kvm_state->hdr.vmx.vmxon_pa))
return -EINVAL;
if ((kvm_state->vmx.smm.flags & KVM_STATE_NESTED_SMM_GUEST_MODE) &&
if ((kvm_state->hdr.vmx.smm.flags & KVM_STATE_NESTED_SMM_GUEST_MODE) &&
(kvm_state->flags & KVM_STATE_NESTED_GUEST_MODE))
return -EINVAL;
if (kvm_state->vmx.smm.flags &
if (kvm_state->hdr.vmx.smm.flags &
~(KVM_STATE_NESTED_SMM_GUEST_MODE | KVM_STATE_NESTED_SMM_VMXON))
return -EINVAL;
@ -5366,21 +5373,21 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
* nor can VMLAUNCH/VMRESUME be pending. Outside SMM, SMM flags
* must be zero.
*/
if (is_smm(vcpu) ? kvm_state->flags : kvm_state->vmx.smm.flags)
if (is_smm(vcpu) ? kvm_state->flags : kvm_state->hdr.vmx.smm.flags)
return -EINVAL;
if ((kvm_state->vmx.smm.flags & KVM_STATE_NESTED_SMM_GUEST_MODE) &&
!(kvm_state->vmx.smm.flags & KVM_STATE_NESTED_SMM_VMXON))
if ((kvm_state->hdr.vmx.smm.flags & KVM_STATE_NESTED_SMM_GUEST_MODE) &&
!(kvm_state->hdr.vmx.smm.flags & KVM_STATE_NESTED_SMM_VMXON))
return -EINVAL;
vmx_leave_nested(vcpu);
if (kvm_state->vmx.vmxon_pa == -1ull)
if (kvm_state->hdr.vmx.vmxon_pa == -1ull)
return 0;
if (kvm_state->flags & KVM_STATE_NESTED_EVMCS)
nested_enable_evmcs(vcpu, NULL);
vmx->nested.vmxon_ptr = kvm_state->vmx.vmxon_pa;
vmx->nested.vmxon_ptr = kvm_state->hdr.vmx.vmxon_pa;
ret = enter_vmx_operation(vcpu);
if (ret)
return ret;
@ -5389,12 +5396,12 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
if (kvm_state->size < sizeof(*kvm_state) + sizeof(*vmcs12))
return 0;
if (kvm_state->vmx.vmcs_pa != -1ull) {
if (kvm_state->vmx.vmcs_pa == kvm_state->vmx.vmxon_pa ||
!page_address_valid(vcpu, kvm_state->vmx.vmcs_pa))
if (kvm_state->hdr.vmx.vmcs12_pa != -1ull) {
if (kvm_state->hdr.vmx.vmcs12_pa == kvm_state->hdr.vmx.vmxon_pa ||
!page_address_valid(vcpu, kvm_state->hdr.vmx.vmcs12_pa))
return -EINVAL;
set_current_vmptr(vmx, kvm_state->vmx.vmcs_pa);
set_current_vmptr(vmx, kvm_state->hdr.vmx.vmcs12_pa);
} else if (kvm_state->flags & KVM_STATE_NESTED_EVMCS) {
/*
* Sync eVMCS upon entry as we may not have
@ -5405,16 +5412,16 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
return -EINVAL;
}
if (kvm_state->vmx.smm.flags & KVM_STATE_NESTED_SMM_VMXON) {
if (kvm_state->hdr.vmx.smm.flags & KVM_STATE_NESTED_SMM_VMXON) {
vmx->nested.smm.vmxon = true;
vmx->nested.vmxon = false;
if (kvm_state->vmx.smm.flags & KVM_STATE_NESTED_SMM_GUEST_MODE)
if (kvm_state->hdr.vmx.smm.flags & KVM_STATE_NESTED_SMM_GUEST_MODE)
vmx->nested.smm.guest_mode = true;
}
vmcs12 = get_vmcs12(vcpu);
if (copy_from_user(vmcs12, user_kvm_nested_state->data, sizeof(*vmcs12)))
if (copy_from_user(vmcs12, user_vmx_nested_state->vmcs12, sizeof(*vmcs12)))
return -EFAULT;
if (vmcs12->hdr.revision_id != VMCS12_REVISION)
@ -5431,12 +5438,14 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
vmcs12->vmcs_link_pointer != -1ull) {
struct vmcs12 *shadow_vmcs12 = get_shadow_vmcs12(vcpu);
if (kvm_state->size < sizeof(*kvm_state) + VMCS12_SIZE + sizeof(*vmcs12))
if (kvm_state->size <
sizeof(*kvm_state) +
sizeof(user_vmx_nested_state->vmcs12) + sizeof(*shadow_vmcs12))
goto error_guest_mode;
if (copy_from_user(shadow_vmcs12,
user_kvm_nested_state->data + VMCS12_SIZE,
sizeof(*vmcs12))) {
user_vmx_nested_state->shadow_vmcs12,
sizeof(*shadow_vmcs12))) {
ret = -EFAULT;
goto error_guest_mode;
}

5
arch/x86/kvm/vmx/vmcs12.h
View File

@ -201,9 +201,10 @@ struct __packed vmcs12 {
/*
* VMCS12_SIZE is the number of bytes L1 should allocate for the VMXON region
* and any VMCS region. Although only sizeof(struct vmcs12) are used by the
* current implementation, 4K are reserved to avoid future complications.
* current implementation, 4K are reserved to avoid future complications and
* to preserve userspace ABI.
*/
#define VMCS12_SIZE 0x1000
#define VMCS12_SIZE KVM_STATE_NESTED_VMX_VMCS_SIZE
/*
* VMCS12_MAX_FIELD_INDEX is the highest index value used in any

2
tools/arch/x86/include/uapi/asm/kvm.h
View File

@ -392,7 +392,7 @@ struct kvm_sync_regs {
struct kvm_vmx_nested_state {
__u64 vmxon_pa;
__u64 vmcs_pa;
__u64 vmcs12_pa;
struct {
__u16 flags;

42
tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c
View File

@ -75,7 +75,7 @@ void set_revision_id_for_vmcs12(struct kvm_nested_state *state,
u32 vmcs12_revision)
{
/* Set revision_id in vmcs12 to vmcs12_revision. */
memcpy(state->data, &vmcs12_revision, sizeof(u32));
memcpy(&state->data, &vmcs12_revision, sizeof(u32));
}
void set_default_state(struct kvm_nested_state *state)
@ -95,9 +95,9 @@ void set_default_vmx_state(struct kvm_nested_state *state, int size)
KVM_STATE_NESTED_EVMCS;
state->format = 0;
state->size = size;
state->vmx.vmxon_pa = 0x1000;
state->vmx.vmcs_pa = 0x2000;
state->vmx.smm.flags = 0;
state->hdr.vmx.vmxon_pa = 0x1000;
state->hdr.vmx.vmcs12_pa = 0x2000;
state->hdr.vmx.smm.flags = 0;
set_revision_id_for_vmcs12(state, VMCS12_REVISION);
}
@ -126,7 +126,7 @@ void test_vmx_nested_state(struct kvm_vm *vm)
* is set to -1ull.
*/
set_default_vmx_state(state, state_sz);
state->vmx.vmxon_pa = -1ull;
state->hdr.vmx.vmxon_pa = -1ull;
test_nested_state(vm, state);
/* Enable VMX in the guest CPUID. */
@ -134,14 +134,14 @@ void test_vmx_nested_state(struct kvm_vm *vm)
/* It is invalid to have vmxon_pa == -1ull and SMM flags non-zero. */
set_default_vmx_state(state, state_sz);
state->vmx.vmxon_pa = -1ull;
state->vmx.smm.flags = 1;
state->hdr.vmx.vmxon_pa = -1ull;
state->hdr.vmx.smm.flags = 1;
test_nested_state_expect_einval(vm, state);
/* It is invalid to have vmxon_pa == -1ull and vmcs_pa != -1ull. */
set_default_vmx_state(state, state_sz);
state->vmx.vmxon_pa = -1ull;
state->vmx.vmcs_pa = 0;
state->hdr.vmx.vmxon_pa = -1ull;
state->hdr.vmx.vmcs12_pa = 0;
test_nested_state_expect_einval(vm, state);
/*
@ -149,13 +149,13 @@ void test_vmx_nested_state(struct kvm_vm *vm)
* setting the nested state.
*/
set_default_vmx_state(state, state_sz);
state->vmx.vmxon_pa = -1ull;
state->vmx.vmcs_pa = -1ull;
state->hdr.vmx.vmxon_pa = -1ull;
state->hdr.vmx.vmcs12_pa = -1ull;
test_nested_state(vm, state);
/* It is invalid to have vmxon_pa set to a non-page aligned address. */
set_default_vmx_state(state, state_sz);
state->vmx.vmxon_pa = 1;
state->hdr.vmx.vmxon_pa = 1;
test_nested_state_expect_einval(vm, state);
/*
@ -165,7 +165,7 @@ void test_vmx_nested_state(struct kvm_vm *vm)
set_default_vmx_state(state, state_sz);
state->flags = KVM_STATE_NESTED_GUEST_MODE |
KVM_STATE_NESTED_RUN_PENDING;
state->vmx.smm.flags = KVM_STATE_NESTED_SMM_GUEST_MODE;
state->hdr.vmx.smm.flags = KVM_STATE_NESTED_SMM_GUEST_MODE;
test_nested_state_expect_einval(vm, state);
/*
@ -174,14 +174,14 @@ void test_vmx_nested_state(struct kvm_vm *vm)
* KVM_STATE_NESTED_SMM_VMXON
*/
set_default_vmx_state(state, state_sz);
state->vmx.smm.flags = ~(KVM_STATE_NESTED_SMM_GUEST_MODE |
state->hdr.vmx.smm.flags = ~(KVM_STATE_NESTED_SMM_GUEST_MODE |
KVM_STATE_NESTED_SMM_VMXON);
test_nested_state_expect_einval(vm, state);
/* Outside SMM, SMM flags must be zero. */
set_default_vmx_state(state, state_sz);
state->flags = 0;
state->vmx.smm.flags = KVM_STATE_NESTED_SMM_GUEST_MODE;
state->hdr.vmx.smm.flags = KVM_STATE_NESTED_SMM_GUEST_MODE;
test_nested_state_expect_einval(vm, state);
/* Size must be large enough to fit kvm_nested_state and vmcs12. */
@ -191,8 +191,8 @@ void test_vmx_nested_state(struct kvm_vm *vm)
/* vmxon_pa cannot be the same address as vmcs_pa. */
set_default_vmx_state(state, state_sz);
state->vmx.vmxon_pa = 0;
state->vmx.vmcs_pa = 0;
state->hdr.vmx.vmxon_pa = 0;
state->hdr.vmx.vmcs12_pa = 0;
test_nested_state_expect_einval(vm, state);
/* The revision id for vmcs12 must be VMCS12_REVISION. */
@ -205,16 +205,16 @@ void test_vmx_nested_state(struct kvm_vm *vm)
* it again.
*/
set_default_vmx_state(state, state_sz);
state->vmx.vmxon_pa = -1ull;
state->vmx.vmcs_pa = -1ull;
state->hdr.vmx.vmxon_pa = -1ull;
state->hdr.vmx.vmcs12_pa = -1ull;
state->flags = 0;
test_nested_state(vm, state);
vcpu_nested_state_get(vm, VCPU_ID, state);
TEST_ASSERT(state->size >= sizeof(*state) && state->size <= state_sz,
"Size must be between %d and %d. The size returned was %d.",
sizeof(*state), state_sz, state->size);
TEST_ASSERT(state->vmx.vmxon_pa == -1ull, "vmxon_pa must be -1ull.");
TEST_ASSERT(state->vmx.vmcs_pa == -1ull, "vmcs_pa must be -1ull.");
TEST_ASSERT(state->hdr.vmx.vmxon_pa == -1ull, "vmxon_pa must be -1ull.");
TEST_ASSERT(state->hdr.vmx.vmcs12_pa == -1ull, "vmcs_pa must be -1ull.");
free(state);
}