On 8/17/2017 9:17 PM, Paolo Bonzini wrote:
On 17/08/2017 14:23, Yu Zhang wrote:On 8/17/2017 8:29 PM, Paolo Bonzini wrote:On 17/08/2017 21:52, Yu Zhang wrote:diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h index ac15193..3e759cf 100644 --- a/arch/x86/kvm/cpuid.h +++ b/arch/x86/kvm/cpuid.h @@ -21,7 +21,14 @@ int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu, int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid, struct kvm_cpuid_entry2 __user *entries); -void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx); + +enum { + NO_CHECK_LIMIT = 0, + CHECK_LIMIT = 1, +};emulate.c should not include cpuid.h. The argument can be simply a bool, though.Thanks, Paolo. So we just use true/false in emulate.c & svm.c, is this OK? BTW could you please+bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, + u32 *ecx, u32 *edx, int check_limit); int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu); diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index fb00559..46daa37 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -28,6 +28,7 @@ #include "x86.h" #include "tss.h" +#include "cpuid.h" /* * Operand types @@ -2333,8 +2334,10 @@ static int emulator_has_longmode(struct x86_emulate_ctxt *ctxt) eax = 0x80000001; ecx = 0; - ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx); - return edx & bit(X86_FEATURE_LM); + if (ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx, NO_CHECK_LIMIT)) + return edx & bit(X86_FEATURE_LM); + else + return 0; } #define GET_SMSTATE(type, smbase, offset) \ @@ -2636,7 +2639,7 @@ static bool vendor_intel(struct x86_emulate_ctxt *ctxt) u32 eax, ebx, ecx, edx; eax = ecx = 0; - ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx); + ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx, NO_CHECK_LIMIT); return ebx == X86EMUL_CPUID_VENDOR_GenuineIntel_ebx && ecx == X86EMUL_CPUID_VENDOR_GenuineIntel_ecx && edx == X86EMUL_CPUID_VENDOR_GenuineIntel_edx; @@ -2656,7 +2659,7 @@ static bool em_syscall_is_enabled(struct x86_emulate_ctxt *ctxt) eax = 0x00000000; ecx = 0x00000000; - ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx); + ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx, NO_CHECK_LIMIT); /* * Intel ("GenuineIntel") * remark: Intel CPUs only support "syscall" in 64bit @@ -3551,7 +3554,7 @@ static int em_movbe(struct x86_emulate_ctxt *ctxt) /* * Check MOVBE is set in the guest-visible CPUID leaf. */ - ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx); + ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx, CHECK_LIMIT);This should be NO_CHECK_LIMIT. Otherwise okay!Then I guess check_fxsr() should also use NO_CHECK_LIMIT('false' for a bool argument), because it's also for eax=1?Good point.And what about svm_vcpu_reset()?No, this one should be left as is, it's just writing a register and not checking a feature.
Got it. Thanks.
I am not sure if leaf 1 is always available. And if the answer is yes, I do not think any of these 3 places(em_movbe/check_fxsr/svm_vcpu_reset) will need to fall back to check_cpuid_limit(), nor do we need to check the return value of get_cpuid(). Do you agree? :-)I think the answer is no, but you don't need to check the return value because testing against 0 is okay (if best is NULL, get_cpuid returns 0 for eax/ebx/ecx/edx).
OK. And to return 0 for eax/ebx/ecx/edx if check_cpuid_limit() is also to be omitted, I'd better refactor this patch and move the "out:" before the if statement. :-)
best = check_cpuid_limit(vcpu, function, index);
}
+out:
if (best) {
*eax = best->eax;
*ebx = best->ebx;
@@ -887,7 +888,6 @@ bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32
*ebx,
} else
*eax = *ebx = *ecx = *edx = 0;
-out:
trace_kvm_cpuid(function, *eax, *ebx, *ecx, *edx, entry_found);
return entry_found;
}
And for all get_cpuid() callers which is testing the existence of a
feature, we do not need to
check the return value, just checking the flag in the register should be
fine, correct?
Yu
PaoloYuPaoloif (!(ecx & FFL(MOVBE))) return emulate_ud(ctxt); @@ -3865,7 +3868,7 @@ static int em_cpuid(struct x86_emulate_ctxt *ctxt) eax = reg_read(ctxt, VCPU_REGS_RAX); ecx = reg_read(ctxt, VCPU_REGS_RCX); - ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx); + ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx, CHECK_LIMIT); *reg_write(ctxt, VCPU_REGS_RAX) = eax; *reg_write(ctxt, VCPU_REGS_RBX) = ebx; *reg_write(ctxt, VCPU_REGS_RCX) = ecx; @@ -3924,7 +3927,7 @@ static int check_fxsr(struct x86_emulate_ctxt *ctxt) { u32 eax = 1, ebx, ecx = 0, edx; - ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx); + ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx, CHECK_LIMIT); if (!(edx & FFL(FXSR))) return emulate_ud(ctxt); diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 1fa9ee5..9def4a8 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1580,7 +1580,7 @@ static void svm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) } init_vmcb(svm); - kvm_cpuid(vcpu, &eax, &dummy, &dummy, &dummy); + kvm_cpuid(vcpu, &eax, &dummy, &dummy, &dummy, CHECK_LIMIT); kvm_register_write(vcpu, VCPU_REGS_RDX, eax); if (kvm_vcpu_apicv_active(vcpu) && !init_event) diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h index 0a6cc67..8a202c4 100644 --- a/arch/x86/kvm/trace.h +++ b/arch/x86/kvm/trace.h @@ -151,8 +151,8 @@ TRACE_EVENT(kvm_fast_mmio, */ TRACE_EVENT(kvm_cpuid, TP_PROTO(unsigned int function, unsigned long rax, unsigned long rbx, - unsigned long rcx, unsigned long rdx), - TP_ARGS(function, rax, rbx, rcx, rdx), + unsigned long rcx, unsigned long rdx, bool found), + TP_ARGS(function, rax, rbx, rcx, rdx, found), TP_STRUCT__entry( __field( unsigned int, function ) @@ -160,6 +160,7 @@ TRACE_EVENT(kvm_cpuid, __field( unsigned long, rbx ) __field( unsigned long, rcx ) __field( unsigned long, rdx ) + __field( bool, found ) ), TP_fast_assign( @@ -168,11 +169,13 @@ TRACE_EVENT(kvm_cpuid, __entry->rbx = rbx; __entry->rcx = rcx; __entry->rdx = rdx; + __entry->found = found; ), - TP_printk("func %x rax %lx rbx %lx rcx %lx rdx %lx", + TP_printk("func %x rax %lx rbx %lx rcx %lx rdx %lx, cpuid entry %s", __entry->function, __entry->rax, - __entry->rbx, __entry->rcx, __entry->rdx) + __entry->rbx, __entry->rcx, __entry->rdx, + __entry->found ? "found" : "not found") ); #define AREG(x) { APIC_##x, "APIC_" #x } diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e40a779..ee99fc1 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5213,10 +5213,10 @@ static int emulator_intercept(struct x86_emulate_ctxt *ctxt, return kvm_x86_ops->check_intercept(emul_to_vcpu(ctxt), info, stage); } -static void emulator_get_cpuid(struct x86_emulate_ctxt *ctxt, - u32 *eax, u32 *ebx, u32 *ecx, u32 *edx) +static bool emulator_get_cpuid(struct x86_emulate_ctxt *ctxt, + u32 *eax, u32 *ebx, u32 *ecx, u32 *edx, int check_limit) { - kvm_cpuid(emul_to_vcpu(ctxt), eax, ebx, ecx, edx); + return kvm_cpuid(emul_to_vcpu(ctxt), eax, ebx, ecx, edx, check_limit); } static ulong emulator_read_gpr(struct x86_emulate_ctxt *ctxt, unsigned reg)
