Re: [PATCH 5/5] VMX: Test behavior on set and cleared save/load debug controls

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2014-06-16 13:02, Paolo Bonzini wrote:
> Il 15/06/2014 16:24, Jan Kiszka ha scritto:
>> From: Jan Kiszka <jan.kiszka@siemens.com>
>>
>> This particularly checks the case when debug controls are not to be
>> loaded/saved on host-guest transitions.
>>
>> We have to fake results related to IA32_DEBUGCTL as support for this MSR
>> is missing KVM. The test already contains all bits required once KVM
>> adds support.
>>
>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>> ---
>>  x86/vmx.h       |   2 ++
>>  x86/vmx_tests.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  2 files changed, 112 insertions(+)
>>
>> diff --git a/x86/vmx.h b/x86/vmx.h
>> index 38ec3c5..3c4830f 100644
>> --- a/x86/vmx.h
>> +++ b/x86/vmx.h
>> @@ -326,6 +326,7 @@ enum Reason {
>>  #define X86_EFLAGS_ZF	0x00000040 /* Zero Flag */
>>  
>>  enum Ctrl_exi {
>> +	EXI_SAVE_DBGCTLS	= 1UL << 2,
>>  	EXI_HOST_64             = 1UL << 9,
>>  	EXI_LOAD_PERF		= 1UL << 12,
>>  	EXI_INTA                = 1UL << 15,
>> @@ -337,6 +338,7 @@ enum Ctrl_exi {
>>  };
>>  
>>  enum Ctrl_ent {
>> +	ENT_LOAD_DBGCTLS	= 1UL << 2,
>>  	ENT_GUEST_64            = 1UL << 9,
>>  	ENT_LOAD_PAT		= 1UL << 14,
>>  	ENT_LOAD_EFER           = 1UL << 15,
>> diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
>> index d0b67de..0f4cfc2 100644
>> --- a/x86/vmx_tests.c
>> +++ b/x86/vmx_tests.c
>> @@ -1406,6 +1406,114 @@ static int interrupt_exit_handler(void)
>>  	return VMX_TEST_VMEXIT;
>>  }
>>  
>> +static int dbgctls_init(struct vmcs *vmcs)
>> +{
>> +	u64 dr7 = 0x402;
>> +	u64 zero = 0;
>> +
>> +	msr_bmp_init();
>> +	asm volatile(
>> +		"mov %0,%%dr0\n\t"
>> +		"mov %0,%%dr1\n\t"
>> +		"mov %0,%%dr2\n\t"
>> +		"mov %1,%%dr7\n\t"
>> +		: : "r" (zero), "r" (dr7));
>> +	wrmsr(MSR_IA32_DEBUGCTLMSR, 0x1);
>> +	vmcs_write(GUEST_DR7, 0x404);
>> +	vmcs_write(GUEST_DEBUGCTL, 0x2);
>> +
>> +	vmcs_write(ENT_CONTROLS, vmcs_read(ENT_CONTROLS) | ENT_LOAD_DBGCTLS);
>> +	vmcs_write(EXI_CONTROLS, vmcs_read(EXI_CONTROLS) | EXI_SAVE_DBGCTLS);
>> +
>> +	return VMX_TEST_START;
>> +}
>> +
>> +static void dbgctls_main(void)
>> +{
>> +	u64 dr7, debugctl;
>> +
>> +	asm volatile("mov %%dr7,%0" : "=r" (dr7));
>> +	debugctl = rdmsr(MSR_IA32_DEBUGCTLMSR);
>> +	debugctl = 0x2; /* KVM does not support DEBUGCTL so far */
>> +	report("Load debug controls", dr7 == 0x404 && debugctl == 0x2);
> 
> Please comment instead like this:
> 
> 	report("Load debug controls", dr7 == 0x404 /* && debugctl == 0x2 */ );
> 
>> +	asm volatile("mov %%dr7,%0" : "=r" (dr7));
>> +	debugctl = rdmsr(MSR_IA32_DEBUGCTLMSR);
>> +	debugctl = 0x1; /* no KVM support */
>> +	report("Guest=host debug controls", dr7 == 0x402 && debugctl == 0x1);
> 
> Same here.
> 
>> +			if (dr7 == 0x400 && debugctl == 0 &&
>> +			    vmcs_read(GUEST_DR7) == 0x408 &&
>> +			    vmcs_read(GUEST_DEBUGCTL) == /* 0x3 no KVM support*/ 0x2)
> 
> and here.
> 
>> +				set_stage(1);
>> +			break;
>> +		case 2:
>> +			dr7 = 0x402;
>> +			asm volatile("mov %0,%%dr7" : : "r" (dr7));
>> +			wrmsr(MSR_IA32_DEBUGCTLMSR, 0x1);
>> +			vmcs_write(GUEST_DR7, 0x404);
>> +			vmcs_write(GUEST_DEBUGCTL, 0x2);
>> +
>> +			vmcs_write(ENT_CONTROLS,
>> +				vmcs_read(ENT_CONTROLS) & ~ENT_LOAD_DBGCTLS);
>> +			vmcs_write(EXI_CONTROLS,
>> +				vmcs_read(EXI_CONTROLS) & ~EXI_SAVE_DBGCTLS);
>> +			break;
>> +		case 3:
>> +			if (dr7 == 0x400 && debugctl == 0 &&
>> +			    vmcs_read(GUEST_DR7) == 0x404 &&
>> +			    vmcs_read(GUEST_DEBUGCTL) == 0x2)
> 
> and here too, even though it happens to work.

OK, no problem.

Jan

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