Re: [PATCH 1/1] kvm: nVMX: Checks "VMCS shadowing" with VMCS link pointer for non-root mode VM{READ,WRITE}

From: kernel test robot
Date: Fri Aug 12 2022 - 10:54:56 EST


Hi Yuan,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on kvm/queue]
[also build test ERROR on mst-vhost/linux-next linus/master v5.19 next-20220812]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/Yuan-Yao/kvm-nVMX-Checks-VMCS-shadowing-with-VMCS-link-pointer-for-non-root-mode-VM-READ-WRITE/20220812-095001
base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git queue
config: i386-randconfig-a011 (https://download.01.org/0day-ci/archive/20220812/202208122237.cw837245-lkp@xxxxxxxxx/config)
compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 5f1c7e2cc5a3c07cbc2412e851a7283c1841f520)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/b15f3d4cd8e8f9cf2db64711234ca27ac74142b2
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Yuan-Yao/kvm-nVMX-Checks-VMCS-shadowing-with-VMCS-link-pointer-for-non-root-mode-VM-READ-WRITE/20220812-095001
git checkout b15f3d4cd8e8f9cf2db64711234ca27ac74142b2
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash arch/x86/kvm/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All errors (new ones prefixed by >>):

>> arch/x86/kvm/vmx/nested.c:5126:35: error: incompatible pointer types passing 'struct kvm_vcpu *' to parameter of type 'struct vmcs12 *' [-Werror,-Wincompatible-pointer-types]
nested_cpu_has_shadow_vmcs(vcpu) &&
^~~~
include/linux/compiler.h:56:47: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^~~~
include/linux/compiler.h:58:52: note: expanded from macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~
arch/x86/kvm/vmx/nested.h:215:62: note: passing argument to parameter 'vmcs12' here
static inline bool nested_cpu_has_shadow_vmcs(struct vmcs12 *vmcs12)
^
>> arch/x86/kvm/vmx/nested.c:5126:35: error: incompatible pointer types passing 'struct kvm_vcpu *' to parameter of type 'struct vmcs12 *' [-Werror,-Wincompatible-pointer-types]
nested_cpu_has_shadow_vmcs(vcpu) &&
^~~~
include/linux/compiler.h:56:47: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^~~~
include/linux/compiler.h:58:61: note: expanded from macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~
arch/x86/kvm/vmx/nested.h:215:62: note: passing argument to parameter 'vmcs12' here
static inline bool nested_cpu_has_shadow_vmcs(struct vmcs12 *vmcs12)
^
>> arch/x86/kvm/vmx/nested.c:5126:35: error: incompatible pointer types passing 'struct kvm_vcpu *' to parameter of type 'struct vmcs12 *' [-Werror,-Wincompatible-pointer-types]
nested_cpu_has_shadow_vmcs(vcpu) &&
^~~~
include/linux/compiler.h:56:47: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^~~~
include/linux/compiler.h:58:86: note: expanded from macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~
include/linux/compiler.h:69:3: note: expanded from macro '__trace_if_value'
(cond) ? \
^~~~
arch/x86/kvm/vmx/nested.h:215:62: note: passing argument to parameter 'vmcs12' here
static inline bool nested_cpu_has_shadow_vmcs(struct vmcs12 *vmcs12)
^
arch/x86/kvm/vmx/nested.c:5237:34: error: incompatible pointer types passing 'struct kvm_vcpu *' to parameter of type 'struct vmcs12 *' [-Werror,-Wincompatible-pointer-types]
nested_cpu_has_shadow_vmcs(vcpu) &&
^~~~
include/linux/compiler.h:56:47: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^~~~
include/linux/compiler.h:58:52: note: expanded from macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~
arch/x86/kvm/vmx/nested.h:215:62: note: passing argument to parameter 'vmcs12' here
static inline bool nested_cpu_has_shadow_vmcs(struct vmcs12 *vmcs12)
^
arch/x86/kvm/vmx/nested.c:5237:34: error: incompatible pointer types passing 'struct kvm_vcpu *' to parameter of type 'struct vmcs12 *' [-Werror,-Wincompatible-pointer-types]
nested_cpu_has_shadow_vmcs(vcpu) &&
^~~~
include/linux/compiler.h:56:47: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^~~~
include/linux/compiler.h:58:61: note: expanded from macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~
arch/x86/kvm/vmx/nested.h:215:62: note: passing argument to parameter 'vmcs12' here
static inline bool nested_cpu_has_shadow_vmcs(struct vmcs12 *vmcs12)
^
arch/x86/kvm/vmx/nested.c:5237:34: error: incompatible pointer types passing 'struct kvm_vcpu *' to parameter of type 'struct vmcs12 *' [-Werror,-Wincompatible-pointer-types]
nested_cpu_has_shadow_vmcs(vcpu) &&
^~~~
include/linux/compiler.h:56:47: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^~~~
include/linux/compiler.h:58:86: note: expanded from macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~
include/linux/compiler.h:69:3: note: expanded from macro '__trace_if_value'
(cond) ? \
^~~~
arch/x86/kvm/vmx/nested.h:215:62: note: passing argument to parameter 'vmcs12' here
static inline bool nested_cpu_has_shadow_vmcs(struct vmcs12 *vmcs12)
^
6 errors generated.


vim +5126 arch/x86/kvm/vmx/nested.c

5098
5099 static int handle_vmread(struct kvm_vcpu *vcpu)
5100 {
5101 struct vmcs12 *vmcs12 = is_guest_mode(vcpu) ? get_shadow_vmcs12(vcpu)
5102 : get_vmcs12(vcpu);
5103 unsigned long exit_qualification = vmx_get_exit_qual(vcpu);
5104 u32 instr_info = vmcs_read32(VMX_INSTRUCTION_INFO);
5105 struct vcpu_vmx *vmx = to_vmx(vcpu);
5106 struct x86_exception e;
5107 unsigned long field;
5108 u64 value;
5109 gva_t gva = 0;
5110 short offset;
5111 int len, r;
5112
5113 if (!nested_vmx_check_permission(vcpu))
5114 return 1;
5115
5116 /* Decode instruction info and find the field to read */
5117 field = kvm_register_read(vcpu, (((instr_info) >> 28) & 0xf));
5118
5119 if (!evmptr_is_valid(vmx->nested.hv_evmcs_vmptr)) {
5120 /*
5121 * In VMX non-root operation, when the VMCS-link pointer is INVALID_GPA,
5122 * any VMREAD sets the ALU flags for VMfailInvalid.
5123 */
5124 if (vmx->nested.current_vmptr == INVALID_GPA ||
5125 (is_guest_mode(vcpu) &&
> 5126 nested_cpu_has_shadow_vmcs(vcpu) &&
5127 get_vmcs12(vcpu)->vmcs_link_pointer == INVALID_GPA))
5128 return nested_vmx_failInvalid(vcpu);
5129
5130 offset = get_vmcs12_field_offset(field);
5131 if (offset < 0)
5132 return nested_vmx_fail(vcpu, VMXERR_UNSUPPORTED_VMCS_COMPONENT);
5133
5134 if (!is_guest_mode(vcpu) && is_vmcs12_ext_field(field))
5135 copy_vmcs02_to_vmcs12_rare(vcpu, vmcs12);
5136
5137 /* Read the field, zero-extended to a u64 value */
5138 value = vmcs12_read_any(vmcs12, field, offset);
5139 } else {
5140 /*
5141 * Hyper-V TLFS (as of 6.0b) explicitly states, that while an
5142 * enlightened VMCS is active VMREAD/VMWRITE instructions are
5143 * unsupported. Unfortunately, certain versions of Windows 11
5144 * don't comply with this requirement which is not enforced in
5145 * genuine Hyper-V. Allow VMREAD from an enlightened VMCS as a
5146 * workaround, as misbehaving guests will panic on VM-Fail.
5147 * Note, enlightened VMCS is incompatible with shadow VMCS so
5148 * all VMREADs from L2 should go to L1.
5149 */
5150 if (WARN_ON_ONCE(is_guest_mode(vcpu)))
5151 return nested_vmx_failInvalid(vcpu);
5152
5153 offset = evmcs_field_offset(field, NULL);
5154 if (offset < 0)
5155 return nested_vmx_fail(vcpu, VMXERR_UNSUPPORTED_VMCS_COMPONENT);
5156
5157 /* Read the field, zero-extended to a u64 value */
5158 value = evmcs_read_any(vmx->nested.hv_evmcs, field, offset);
5159 }
5160
5161 /*
5162 * Now copy part of this value to register or memory, as requested.
5163 * Note that the number of bits actually copied is 32 or 64 depending
5164 * on the guest's mode (32 or 64 bit), not on the given field's length.
5165 */
5166 if (instr_info & BIT(10)) {
5167 kvm_register_write(vcpu, (((instr_info) >> 3) & 0xf), value);
5168 } else {
5169 len = is_64_bit_mode(vcpu) ? 8 : 4;
5170 if (get_vmx_mem_address(vcpu, exit_qualification,
5171 instr_info, true, len, &gva))
5172 return 1;
5173 /* _system ok, nested_vmx_check_permission has verified cpl=0 */
5174 r = kvm_write_guest_virt_system(vcpu, gva, &value, len, &e);
5175 if (r != X86EMUL_CONTINUE)
5176 return kvm_handle_memory_failure(vcpu, r, &e);
5177 }
5178
5179 return nested_vmx_succeed(vcpu);
5180 }
5181

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