From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60104) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f1FDs-0000B2-9W for qemu-devel@nongnu.org; Wed, 28 Mar 2018 13:50:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f1FDp-0002R7-6n for qemu-devel@nongnu.org; Wed, 28 Mar 2018 13:50:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42644) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1f1FDo-0002Pa-UJ for qemu-devel@nongnu.org; Wed, 28 Mar 2018 13:50:53 -0400 Date: Wed, 28 Mar 2018 14:50:50 -0300 From: Eduardo Habkost Message-ID: <20180328175050.GH5046@localhost.localdomain> References: <20180326170658.606-1-juterry@microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180326170658.606-1-juterry@microsoft.com> Subject: Re: [Qemu-devel] [PATCH] WHPX fixes an issue with CPUID 1 not returning CPUID_EXT_HYPERVISOR List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Justin Terry (VM)" Cc: qemu-devel@nongnu.org, pbonzini@redhat.com, rth@twiddle.net On Mon, Mar 26, 2018 at 10:06:58AM -0700, Justin Terry (VM) wrote: > Implements the CPUID trap for CPUID 1 to include the > CPUID_EXT_HYPERVISOR flag in the ECX results. This was preventing some > older linux kernels from booting when trying to access MSR's that dont > make sense when virtualized. > > Signed-off-by: Justin Terry (VM) > --- > target/i386/whpx-all.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 78 insertions(+), 1 deletion(-) > > diff --git a/target/i386/whpx-all.c b/target/i386/whpx-all.c > index bf33d320bf..58435178a4 100644 > --- a/target/i386/whpx-all.c > +++ b/target/i386/whpx-all.c > @@ -911,12 +911,62 @@ static int whpx_vcpu_run(CPUState *cpu) > ret = 1; > break; > > + case WHvRunVpExitReasonX64Cpuid: { > + WHV_REGISTER_VALUE reg_values[5] = {0}; > + WHV_REGISTER_NAME reg_names[5]; > + UINT32 reg_count = 5; > + UINT64 rip, rax, rcx, rdx, rbx; > + > + rip = vcpu->exit_ctx.VpContext.Rip + > + vcpu->exit_ctx.VpContext.InstructionLength; > + switch (vcpu->exit_ctx.CpuidAccess.Rax) { > + case 1: > + rax = vcpu->exit_ctx.CpuidAccess.DefaultResultRax; > + /* Advertise that we are running on a hypervisor */ > + rcx = > + vcpu->exit_ctx.CpuidAccess.DefaultResultRcx | > + CPUID_EXT_HYPERVISOR; > + > + rdx = vcpu->exit_ctx.CpuidAccess.DefaultResultRdx; > + rbx = vcpu->exit_ctx.CpuidAccess.DefaultResultRbx; > + break; > + default: > + rax = vcpu->exit_ctx.CpuidAccess.DefaultResultRax; > + rcx = vcpu->exit_ctx.CpuidAccess.DefaultResultRcx; > + rdx = vcpu->exit_ctx.CpuidAccess.DefaultResultRdx; > + rbx = vcpu->exit_ctx.CpuidAccess.DefaultResultRbx; Interesting, so the WHPX API already tries to provide default values for the CPUID leaves. Would it make sense to try and use the values returned by cpu_x86_cpuid() in the future? Is there a way to get the default CPUID results from the WHPX API without calling WHvRunVirtualProcessor(), so QEMU can be aware of what exactly the guest is seeing on CPUID? > + } > + > + reg_names[0] = WHvX64RegisterRip; > + reg_names[1] = WHvX64RegisterRax; > + reg_names[2] = WHvX64RegisterRcx; > + reg_names[3] = WHvX64RegisterRdx; > + reg_names[4] = WHvX64RegisterRbx; > + > + reg_values[0].Reg64 = rip; > + reg_values[1].Reg64 = rax; > + reg_values[2].Reg64 = rcx; > + reg_values[3].Reg64 = rdx; > + reg_values[4].Reg64 = rbx; > + > + hr = WHvSetVirtualProcessorRegisters(whpx->partition, > + cpu->cpu_index, > + reg_names, > + reg_count, > + reg_values); > + > + if (FAILED(hr)) { > + error_report("WHPX: Failed to set CpuidAccess state registers," > + " hr=%08lx", hr); > + } > + ret = 0; > + break; > + } > case WHvRunVpExitReasonNone: > case WHvRunVpExitReasonUnrecoverableException: > case WHvRunVpExitReasonInvalidVpRegisterValue: > case WHvRunVpExitReasonUnsupportedFeature: > case WHvRunVpExitReasonX64MsrAccess: > - case WHvRunVpExitReasonX64Cpuid: > case WHvRunVpExitReasonException: > default: > error_report("WHPX: Unexpected VP exit code %d", > @@ -1272,6 +1322,33 @@ static int whpx_accel_init(MachineState *ms) > goto error; > } > > + memset(&prop, 0, sizeof(WHV_PARTITION_PROPERTY)); > + prop.ExtendedVmExits.X64CpuidExit = 1; > + hr = WHvSetPartitionProperty(whpx->partition, > + WHvPartitionPropertyCodeExtendedVmExits, > + &prop, > + sizeof(WHV_PARTITION_PROPERTY)); > + > + if (FAILED(hr)) { > + error_report("WHPX: Failed to enable partition extended X64CpuidExit" > + " hr=%08lx", hr); > + ret = -EINVAL; > + goto error; > + } > + > + UINT32 cpuidExitList[] = {1}; > + hr = WHvSetPartitionProperty(whpx->partition, > + WHvPartitionPropertyCodeCpuidExitList, > + cpuidExitList, > + RTL_NUMBER_OF(cpuidExitList) * sizeof(UINT32)); > + > + if (FAILED(hr)) { > + error_report("WHPX: Failed to set partition CpuidExitList hr=%08lx", > + hr); > + ret = -EINVAL; > + goto error; > + } > + > hr = WHvSetupPartition(whpx->partition); > if (FAILED(hr)) { > error_report("WHPX: Failed to setup partition, hr=%08lx", hr); > -- > 2.11.0 > -- Eduardo