On Wed, 2023-11-08 at 11:17 +0000, Nicolas Saenz Julienne wrote:
> The hypercall page patching is about to grow considerably, move it into
> its own function.
>
> No functional change intended.
>
> Signed-off-by: Nicolas Saenz Julienne <[email protected]>
> ---
> arch/x86/kvm/hyperv.c | 69 ++++++++++++++++++++++++-------------------
> 1 file changed, 39 insertions(+), 30 deletions(-)
>
> diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
> index e1bc861ab3b0..78d053042667 100644
> --- a/arch/x86/kvm/hyperv.c
> +++ b/arch/x86/kvm/hyperv.c
> @@ -256,6 +256,42 @@ static void synic_exit(struct kvm_vcpu_hv_synic *synic, u32 msr)
> kvm_make_request(KVM_REQ_HV_EXIT, vcpu);
> }
>
> +static int patch_hypercall_page(struct kvm_vcpu *vcpu, u64 data)
> +{
> + struct kvm *kvm = vcpu->kvm;
> + u8 instructions[9];
> + int i = 0;
> + u64 addr;
> +
> + /*
> + * If Xen and Hyper-V hypercalls are both enabled, disambiguate
> + * the same way Xen itself does, by setting the bit 31 of EAX
> + * which is RsvdZ in the 32-bit Hyper-V hypercall ABI and just
> + * going to be clobbered on 64-bit.
> + */
> + if (kvm_xen_hypercall_enabled(kvm)) {
> + /* orl $0x80000000, %eax */
> + instructions[i++] = 0x0d;
> + instructions[i++] = 0x00;
> + instructions[i++] = 0x00;
> + instructions[i++] = 0x00;
> + instructions[i++] = 0x80;
> + }
> +
> + /* vmcall/vmmcall */
> + static_call(kvm_x86_patch_hypercall)(vcpu, instructions + i);
> + i += 3;
> +
> + /* ret */
> + ((unsigned char *)instructions)[i++] = 0xc3;
> +
> + addr = data & HV_X64_MSR_HYPERCALL_PAGE_ADDRESS_MASK;
> + if (kvm_vcpu_write_guest(vcpu, addr, instructions, i))
> + return 1;
> +
> + return 0;
> +}
> +
> static int synic_set_msr(struct kvm_vcpu_hv_synic *synic,
> u32 msr, u64 data, bool host)
> {
> @@ -1338,11 +1374,7 @@ static int kvm_hv_set_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data,
> if (!hv->hv_guest_os_id)
> hv->hv_hypercall &= ~HV_X64_MSR_HYPERCALL_ENABLE;
> break;
> - case HV_X64_MSR_HYPERCALL: {
> - u8 instructions[9];
> - int i = 0;
> - u64 addr;
> -
> + case HV_X64_MSR_HYPERCALL:
> /* if guest os id is not set hypercall should remain disabled */
> if (!hv->hv_guest_os_id)
> break;
> @@ -1351,34 +1383,11 @@ static int kvm_hv_set_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data,
> break;
> }
>
> - /*
> - * If Xen and Hyper-V hypercalls are both enabled, disambiguate
> - * the same way Xen itself does, by setting the bit 31 of EAX
> - * which is RsvdZ in the 32-bit Hyper-V hypercall ABI and just
> - * going to be clobbered on 64-bit.
> - */
> - if (kvm_xen_hypercall_enabled(kvm)) {
> - /* orl $0x80000000, %eax */
> - instructions[i++] = 0x0d;
> - instructions[i++] = 0x00;
> - instructions[i++] = 0x00;
> - instructions[i++] = 0x00;
> - instructions[i++] = 0x80;
> - }
> -
> - /* vmcall/vmmcall */
> - static_call(kvm_x86_patch_hypercall)(vcpu, instructions + i);
> - i += 3;
> -
> - /* ret */
> - ((unsigned char *)instructions)[i++] = 0xc3;
> -
> - addr = data & HV_X64_MSR_HYPERCALL_PAGE_ADDRESS_MASK;
> - if (kvm_vcpu_write_guest(vcpu, addr, instructions, i))
> + if (patch_hypercall_page(vcpu, data))
> return 1;
> +
> hv->hv_hypercall = data;
> break;
> - }
> case HV_X64_MSR_REFERENCE_TSC:
> hv->hv_tsc_page = data;
> if (hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE) {
This looks like another nice cleanup that can be accepted to the kvm,
before the main VTL patch series.
Reviewed-by: Maxim Levitsky <[email protected]>
Best regards,
Maxim Levitsky