On 01/13/2010 03:59 PM, Gleb Natapov wrote:
Minimum HYPER-V implementation should have GUEST_OS_ID, HYPERCALL and
VP_INDEX MSRs.
diff --git a/arch/x86/include/asm/kvm_hyperv.h b/arch/x86/include/asm/kvm_hyperv.h
new file mode 100644
index 0000000..91211f3
--- /dev/null
+++ b/arch/x86/include/asm/kvm_hyperv.h
Please name this asm/hyperv.h, so it can be used for
Linux-as-Hyper-V-guest, not just Linux-as-host-impersonating-Hyper-V.+
Also put this in a separate patch.
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6811e5e..6972b2b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -628,7 +628,8 @@ 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
End with trailing comma so future patches are nicer.
+static bool kvm_hv_hypercall_enabled(struct kvm *kvm)
+{
+ return !!(kvm->arch.hv_hypercall& HV_X64_MSR_HYPERCALL_ENABLE);
+}
!! is unnecessary for bool:
_Bool and(unsigned x) { return x & 16; }
0000000000000010 <and>:
10: c1 ef 04 shr $0x4,%edi
13: 89 f8 mov %edi,%eax
15: 83 e0 01 and $0x1,%eax
18: c3 retq
+
+static int set_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data)
+{
+ struct kvm *kvm = vcpu->kvm;
+
+ switch (msr) {
+ case HV_X64_MSR_GUEST_OS_ID:
+ kvm->arch.hv_guest_os_id = data;
+ /* setting guest os id to zero disables hypercall page */
+ if (!kvm->arch.hv_guest_os_id)
+ kvm->arch.hv_hypercall&= ~HV_X64_MSR_HYPERCALL_ENABLE;
+ break;
+ 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;
+ kvm_x86_ops->patch_hypercall(vcpu, (unsigned char*)addr);
+ ((unsigned char*)addr)[3] = 0xc3; /* ret */
+ break;
+ }
+ default:
+ pr_unimpl(vcpu, "HYPER-V unimplemented wrmsr: 0x%x "
+ "data 0x%llx\n", msr, data);
+ return 1;
+ }
+ return 0;
+}
We need locking in case a malicious guest issues partition-wide msrs
from multiple vcpus simultaneously.
int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
{
switch (msr) {
@@ -1117,6 +1181,16 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
pr_unimpl(vcpu, "unimplemented perfctr wrmsr: "
"0x%x data 0x%llx\n", msr, data);
break;
+ case HV_X64_MSR_GUEST_OS_ID ... HV_X64_MSR_SINT15:
+ if (kvm_hv_msr_partition_wide(msr)) {
+ int r;
+ mutex_lock(&vcpu->kvm->lock);
+ r = set_msr_hyperv_pw(vcpu, msr, data);
+ mutex_unlock(&vcpu->kvm->lock);
We do have locking. Any reason not to put it in set_msr_hyperv_pw?
Seems cleaner.
+static int get_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
+{
+ u64 data = 0;
+ struct kvm *kvm = vcpu->kvm;
+
+ switch (msr) {
+ case HV_X64_MSR_GUEST_OS_ID:
+ data = kvm->arch.hv_guest_os_id;
+ break;
+ case HV_X64_MSR_HYPERCALL:
+ data = kvm->arch.hv_hypercall;
+ break;
This could be non-atomic on i386. I don't think it matters.
int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
{
unsigned long nr, a0, a1, a2, a3, ret;
int r = 1;
+ if(kvm_hv_hypercall_enabled(vcpu->kvm))
+ return kvm_hv_hypercall(vcpu);
+
Space after if.
--
error compiling committee.c: too many arguments to function
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