Re: [PATCHv2 2/4] Implement bare minimum of HYPER-V MSRs.

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On 01/17/2010 11:03 AM, Gleb Natapov wrote:
Minimum HYPER-V implementation should have GUEST_OS_ID, HYPERCALL and
VP_INDEX MSRs.


  TRACE_EVENT(kvm_pio,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4d835b6..db0b2b1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -630,7 +630,8 @@ static u32 msrs_to_save[] = {
  #ifdef CONFIG_X86_64
  	MSR_CSTAR, MSR_KERNEL_GS_BASE, MSR_SYSCALL_MASK, MSR_LSTAR,
  #endif
-	MSR_IA32_TSC, MSR_IA32_PERF_STATUS, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA
+	MSR_IA32_TSC, MSR_IA32_PERF_STATUS, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA,
+	HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL,
  };

These will be disabled since the msrs don't exist on the host. See the comment above and KVM_SAVE_MSRS_BEGIN.

+	case HV_X64_MSR_HYPERCALL: {
+		u64 gfn;
+		unsigned long addr;
+		/* if guest os id is not set hypercall should remain disabled */
+		if (!kvm->arch.hv_guest_os_id&&  data)
+			break;
+		kvm->arch.hv_hypercall = data;
+		if (!kvm_hv_hypercall_enabled(kvm))
+			break;
+		gfn = kvm->arch.hv_hypercall>>
+			HV_X64_MSR_HYPERCALL_PAGE_ADDRESS_SHIFT;
+		addr = gfn_to_hva(kvm, gfn);
+		if (kvm_is_error_hva(addr))
+			return 1;

Should di the error check before assigning, perhaps.

+		kvm_x86_ops->patch_hypercall(vcpu, (unsigned char *)addr);
+		((unsigned char *)addr)[3] = 0xc3; /* ret */

kvm_write_guest(), this can fault.

+int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
+{
+	u64 param, ingpa, outgpa, ret;
+	uint16_t code, rep_idx, rep_cnt, res = HV_STATUS_SUCCESS, rep_done = 0;
+	bool fast, longmode;
+	int cs_db, cs_l;
+
+	/*
+	 * hypercall generates UD from non zero cpl and real mode
+	 * per HYPER-V spec
+	 */
+	if (kvm_x86_ops->get_cpl(vcpu) != 0 || !(vcpu->arch.cr0&  X86_CR0_PE)) {

Use kvm_read_cr0_bits() to avoid caching.


--
error compiling committee.c: too many arguments to function

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