On Mon, Aug 5, 2013 at 4:29 PM, Gleb Natapov <gleb@xxxxxxxxxx> wrote:
> On Tue, Jul 30, 2013 at 11:41:00PM +0800, Arthur Chunqi Li wrote:
>> Change "rflags" in "struct regs" to "host_rflags". Remove settings
>> to GUEST_RFLAGS since GUEST_RFLAGS can be set by vmwrite. Treat
>> host_rflags as host rflags before and after vmenter.
>>
> I am not sure the change is for the better. Before the change one could
> set up rflags for guest environment by setting regs.rflags, no special
> init function had to be written. I do not see any problem with correct
> code, except that rflags is not correct on a guest entry, but this
> should be easy to fix.
regs.rflags are designed to set guest rflags, but the current
implementation just use it as host_rflags. For every VM entry, it will
load value set by vmcs_write(GUEST_RFLAGS). Set regs.flags as host
rflags and then enter VM cannot affect VM's rflags, which is the
current implementation.
Besides, if host want to set/get guest's rflags, it just use
vmcs_write/read(GUEST_RFLAGS).
Arthur
>
>> Besides, add checks to flags after vmenter.
>>
>> Signed-off-by: Arthur Chunqi Li <yzt356@xxxxxxxxx>
>> ---
>> x86/vmx.c | 11 ++++++-----
>> x86/vmx.h | 2 +-
>> 2 files changed, 7 insertions(+), 6 deletions(-)
>>
>> diff --git a/x86/vmx.c b/x86/vmx.c
>> index 7467927..082c3bb 100644
>> --- a/x86/vmx.c
>> +++ b/x86/vmx.c
>> @@ -481,6 +481,8 @@ static int vmx_run()
>> "vmresume\n\t"
>> "2: "
>> "setbe %0\n\t"
>> + "jbe vmx_return\n\t"
>> + "ud2\n\t"
>> "vmx_return:\n\t"
>> SAVE_GPR_C
>> SAVE_RFLAGS
>> @@ -505,15 +507,15 @@ static int vmx_run()
>> return 0;
>> case VMX_TEST_LAUNCH_ERR:
>> printf("%s : vmlaunch failed.\n", __func__);
>> - if ((!(regs.rflags & X86_EFLAGS_CF) && !(regs.rflags & X86_EFLAGS_ZF))
>> - || ((regs.rflags & X86_EFLAGS_CF) && (regs.rflags & X86_EFLAGS_ZF)))
>> + if ((!(regs.host_rflags & X86_EFLAGS_CF) && !(regs.host_rflags & X86_EFLAGS_ZF))
>> + || ((regs.host_rflags & X86_EFLAGS_CF) && (regs.host_rflags & X86_EFLAGS_ZF)))
>> printf("\tvmlaunch set wrong flags\n");
>> report("test vmlaunch", 0);
>> break;
>> case VMX_TEST_RESUME_ERR:
>> printf("%s : vmresume failed.\n", __func__);
>> - if ((!(regs.rflags & X86_EFLAGS_CF) && !(regs.rflags & X86_EFLAGS_ZF))
>> - || ((regs.rflags & X86_EFLAGS_CF) && (regs.rflags & X86_EFLAGS_ZF)))
>> + if ((!(regs.host_rflags & X86_EFLAGS_CF) && !(regs.host_rflags & X86_EFLAGS_ZF))
>> + || ((regs.host_rflags & X86_EFLAGS_CF) && (regs.host_rflags & X86_EFLAGS_ZF)))
>> printf("\tvmresume set wrong flags\n");
>> report("test vmresume", 0);
>> break;
>> @@ -540,7 +542,6 @@ static int test_run(struct vmx_test *test)
>> test->exits = 0;
>> current = test;
>> regs = test->guest_regs;
>> - vmcs_write(GUEST_RFLAGS, regs.rflags | 0x2);
>> launched = 0;
>> printf("\nTest suite : %s\n", test->name);
>> vmx_run();
>> diff --git a/x86/vmx.h b/x86/vmx.h
>> index 1fb9738..d80e000 100644
>> --- a/x86/vmx.h
>> +++ b/x86/vmx.h
>> @@ -27,7 +27,7 @@ struct regs {
>> u64 r13;
>> u64 r14;
>> u64 r15;
>> - u64 rflags;
>> + u64 host_rflags;
>> };
>>
>> struct vmx_test {
>> --
>> 1.7.9.5
>
> --
> Gleb.
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