On Sun, Jul 7, 2013 at 4:50 PM, Gleb Natapov <gleb@xxxxxxxxxx> wrote: > On Sun, Jul 07, 2013 at 04:47:05PM +0800, Arthur Chunqi Li wrote: >> On Sun, Jul 7, 2013 at 3:20 PM, Gleb Natapov <gleb@xxxxxxxxxx> wrote: >> > On Sun, Jul 07, 2013 at 03:16:08PM +0800, Arthur Chunqi Li wrote: >> >> On Sun, Jul 7, 2013 at 2:59 PM, Gleb Natapov <gleb@xxxxxxxxxx> wrote: >> >> > On Fri, Jul 05, 2013 at 11:13:17PM +0800, Arthur Chunqi Li wrote: >> >> >> Fix read/write to IA32_FEATURE_CONTROL MSR in nested environment. >> >> >> >> >> >> This patch simulate this MSR in nested_vmx and the default value is >> >> >> 0x0. BIOS should set it to 0x5 before VMXON. After setting the lock >> >> >> bit, write to it will cause #GP(0). >> >> >> >> >> >> Signed-off-by: Arthur Chunqi Li <yzt356@xxxxxxxxx> >> >> > The patch is heavily based on Nadav's one. You need to preserve >> >> > authorship. Add From: and Nadav's Sign-off-by. >> >> > >> >> >> --- >> >> >> arch/x86/kvm/vmx.c | 25 +++++++++++++++++++++---- >> >> >> arch/x86/kvm/x86.c | 3 ++- >> >> >> 2 files changed, 23 insertions(+), 5 deletions(-) >> >> >> >> >> >> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >> >> >> index 260a919..5e3d44e 100644 >> >> >> --- a/arch/x86/kvm/vmx.c >> >> >> +++ b/arch/x86/kvm/vmx.c >> >> >> @@ -373,6 +373,7 @@ struct nested_vmx { >> >> >> * we must keep them pinned while L2 runs. >> >> >> */ >> >> >> struct page *apic_access_page; >> >> >> + u64 msr_ia32_feature_control; >> >> >> }; >> >> >> >> >> >> #define POSTED_INTR_ON 0 >> >> >> @@ -2277,8 +2278,11 @@ static int vmx_get_vmx_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata) >> >> >> >> >> >> switch (msr_index) { >> >> >> case MSR_IA32_FEATURE_CONTROL: >> >> >> - *pdata = 0; >> >> >> - break; >> >> >> + if (nested_vmx_allowed(vcpu)){ >> >> >> + *pdata = to_vmx(vcpu)->nested.msr_ia32_feature_control; >> >> >> + break; >> >> >> + } >> >> >> + return 0; >> >> >> case MSR_IA32_VMX_BASIC: >> >> >> /* >> >> >> * This MSR reports some information about VMX support. We >> >> >> @@ -2356,9 +2360,13 @@ static int vmx_set_vmx_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data) >> >> >> if (!nested_vmx_allowed(vcpu)) >> >> >> return 0; >> >> >> >> >> >> - if (msr_index == MSR_IA32_FEATURE_CONTROL) >> >> >> - /* TODO: the right thing. */ >> >> >> + if (msr_index == MSR_IA32_FEATURE_CONTROL){ >> >> >> + if (to_vmx(vcpu)->nested.msr_ia32_feature_control >> >> >> + & FEATURE_CONTROL_LOCKED) >> >> >> + return 0; >> >> >> + to_vmx(vcpu)->nested.msr_ia32_feature_control = data; >> >> > You need to allow setting it from userspace, otherwise reset will not >> >> > clear it. >> >> As to my memory, if the lock bit of IA32_FEATURE_CONTROL is set, this >> >> MSR cannot be set or reset. So what do you mean setting it from >> >> userspace? >> > It can be reset by power cycling CPU obviously, so when userspace emulates >> > power cycle reset it has to be able to zero the MSR. BTW you need to write >> > corespondent QEMU patch to handle this MSR during reset and migration. >> What is the current call trace when QEMU do system_reset? Will it >> trigger vmx_vcpu_reset() in vmx.c? > It will not. QEMU inits vcpu state in userspace and write it into the > kernel with set_regs/set_srges ioctls. So how will this achieve isolation and protection? I mean if QEMU can reset this MSR when reboot, can user in OS also reset it? Actually, after setting to lock bit, it cannot be set until next reboot. > >> > >> >> > >> >> >> return 1; >> >> >> + } >> >> >> /* >> >> >> * No need to treat VMX capability MSRs specially: If we don't handle >> >> >> * them, handle_wrmsr will #GP(0), which is correct (they are readonly) >> >> >> @@ -5595,6 +5603,15 @@ static int handle_vmon(struct kvm_vcpu *vcpu) >> >> >> skip_emulated_instruction(vcpu); >> >> >> return 1; >> >> >> } >> >> >> + >> >> >> +#define VMXON_NEEDED_FEATURES \ >> >> > Avi asked to use const u64 here. >> >> > >> >> >> + (FEATURE_CONTROL_LOCKED | FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX) >> >> >> + if ((vmx->nested.msr_ia32_feature_control & VMXON_NEEDED_FEATURES) >> >> >> + != VMXON_NEEDED_FEATURES) { >> >> >> + kvm_inject_gp(vcpu, 0); >> >> >> + return 1; >> >> >> + } >> >> >> + >> >> >> if (enable_shadow_vmcs) { >> >> >> shadow_vmcs = alloc_vmcs(); >> >> >> if (!shadow_vmcs) >> >> >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> >> >> index e8ba99c..2d4eb8e 100644 >> >> >> --- a/arch/x86/kvm/x86.c >> >> >> +++ b/arch/x86/kvm/x86.c >> >> >> @@ -850,7 +850,8 @@ 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_CR_PAT, MSR_VM_HSAVE_PA >> >> >> + MSR_IA32_TSC, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA, >> >> >> + MSR_IA32_FEATURE_CONTROL >> >> >> }; >> >> >> >> >> >> static unsigned num_msrs_to_save; >> >> >> -- >> >> >> 1.7.9.5 >> >> > >> >> > -- >> >> > Gleb. >> > >> > -- >> > Gleb. >> >> >> >> -- >> Arthur Chunqi Li >> Department of Computer Science >> School of EECS >> Peking University >> Beijing, China > > -- > Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html