* [PATCH] KVM: x86: nVMX: allow RSM to restore VMXE CR4 flag
@ 2019-03-26 13:07 Vitaly Kuznetsov
2019-03-26 13:11 ` Liran Alon
[not found] ` <20190327192946.19128-1-sean.j.christopherson@intel.com>
0 siblings, 2 replies; 10+ messages in thread
From: Vitaly Kuznetsov @ 2019-03-26 13:07 UTC (permalink / raw)
To: kvm
Cc: Paolo Bonzini, Radim Krčmář,
Jon Doron, Sean Christopherson, Liran Alon, linux-kernel
Commit 5bea5123cbf0 ("KVM: VMX: check nested state and CR4.VMXE against
SMM") introduced a check to vmx_set_cr4() forbidding to set VMXE from SMM.
The check is correct, however, there is a special case when RSM is called
to leave SMM: rsm_enter_protected_mode() is called with HF_SMM_MASK still
set and in case VMXE was set before entering SMM we're failing to return.
Resolve the issue by temporary dropping HF_SMM_MASK around set_cr4() calls
when ops->set_cr() is called from RSM.
Reported-by: Jon Doron <arilou@gmail.com>
Suggested-by: Liran Alon <liran.alon@oracle.com>
Fixes: 5bea5123cbf0 ("KVM: VMX: check nested state and CR4.VMXE against SMM")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
- Instread of putting the temporary HF_SMM_MASK drop to
rsm_enter_protected_mode() (as was suggested by Liran), move it to
emulator_set_cr() modifying its interface. emulate.c seems to be
vcpu-specifics-free at this moment, we may want to keep it this way.
- It seems that Hyper-V+UEFI on KVM is still broken, I'm observing sporadic
hangs even with this patch. These hangs, however, seem to be unrelated to
rsm.
---
arch/x86/include/asm/kvm_emulate.h | 3 ++-
arch/x86/kvm/emulate.c | 27 ++++++++++++++-------------
arch/x86/kvm/x86.c | 12 +++++++++++-
3 files changed, 27 insertions(+), 15 deletions(-)
diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index 93c4bf598fb0..6c33caa82fa5 100644
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -203,7 +203,8 @@ struct x86_emulate_ops {
void (*set_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
void (*set_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
ulong (*get_cr)(struct x86_emulate_ctxt *ctxt, int cr);
- int (*set_cr)(struct x86_emulate_ctxt *ctxt, int cr, ulong val);
+ int (*set_cr)(struct x86_emulate_ctxt *ctxt, int cr, ulong val,
+ bool from_rsm);
int (*cpl)(struct x86_emulate_ctxt *ctxt);
int (*get_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong *dest);
int (*set_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong value);
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index c338984c850d..a6204105d4d7 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2413,7 +2413,7 @@ static int rsm_enter_protected_mode(struct x86_emulate_ctxt *ctxt,
cr3 &= ~0xfff;
}
- bad = ctxt->ops->set_cr(ctxt, 3, cr3);
+ bad = ctxt->ops->set_cr(ctxt, 3, cr3, true);
if (bad)
return X86EMUL_UNHANDLEABLE;
@@ -2422,20 +2422,20 @@ static int rsm_enter_protected_mode(struct x86_emulate_ctxt *ctxt,
* Then enable protected mode. However, PCID cannot be enabled
* if EFER.LMA=0, so set it separately.
*/
- bad = ctxt->ops->set_cr(ctxt, 4, cr4 & ~X86_CR4_PCIDE);
+ bad = ctxt->ops->set_cr(ctxt, 4, cr4 & ~X86_CR4_PCIDE, true);
if (bad)
return X86EMUL_UNHANDLEABLE;
- bad = ctxt->ops->set_cr(ctxt, 0, cr0);
+ bad = ctxt->ops->set_cr(ctxt, 0, cr0, true);
if (bad)
return X86EMUL_UNHANDLEABLE;
if (cr4 & X86_CR4_PCIDE) {
- bad = ctxt->ops->set_cr(ctxt, 4, cr4);
+ bad = ctxt->ops->set_cr(ctxt, 4, cr4, true);
if (bad)
return X86EMUL_UNHANDLEABLE;
if (pcid) {
- bad = ctxt->ops->set_cr(ctxt, 3, cr3 | pcid);
+ bad = ctxt->ops->set_cr(ctxt, 3, cr3 | pcid, true);
if (bad)
return X86EMUL_UNHANDLEABLE;
}
@@ -2581,7 +2581,7 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt)
/* Zero CR4.PCIDE before CR0.PG. */
if (cr4 & X86_CR4_PCIDE) {
- ctxt->ops->set_cr(ctxt, 4, cr4 & ~X86_CR4_PCIDE);
+ ctxt->ops->set_cr(ctxt, 4, cr4 & ~X86_CR4_PCIDE, true);
cr4 &= ~X86_CR4_PCIDE;
}
@@ -2595,11 +2595,12 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt)
/* For the 64-bit case, this will clear EFER.LMA. */
cr0 = ctxt->ops->get_cr(ctxt, 0);
if (cr0 & X86_CR0_PE)
- ctxt->ops->set_cr(ctxt, 0, cr0 & ~(X86_CR0_PG | X86_CR0_PE));
+ ctxt->ops->set_cr(ctxt, 0, cr0 & ~(X86_CR0_PG | X86_CR0_PE),
+ true);
/* Now clear CR4.PAE (which must be done before clearing EFER.LME). */
if (cr4 & X86_CR4_PAE)
- ctxt->ops->set_cr(ctxt, 4, cr4 & ~X86_CR4_PAE);
+ ctxt->ops->set_cr(ctxt, 4, cr4 & ~X86_CR4_PAE, true);
/* And finally go back to 32-bit mode. */
efer = 0;
@@ -3131,7 +3132,7 @@ static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt,
int ret;
u8 cpl;
- if (ctxt->ops->set_cr(ctxt, 3, tss->cr3))
+ if (ctxt->ops->set_cr(ctxt, 3, tss->cr3, false))
return emulate_gp(ctxt, 0);
ctxt->_eip = tss->eip;
ctxt->eflags = tss->eflags | 2;
@@ -3331,7 +3332,7 @@ static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt,
write_segment_descriptor(ctxt, tss_selector, &next_tss_desc);
}
- ops->set_cr(ctxt, 0, ops->get_cr(ctxt, 0) | X86_CR0_TS);
+ ops->set_cr(ctxt, 0, ops->get_cr(ctxt, 0) | X86_CR0_TS, false);
ops->set_segment(ctxt, tss_selector, &next_tss_desc, 0, VCPU_SREG_TR);
if (has_error_code) {
@@ -3633,7 +3634,7 @@ static int em_movbe(struct x86_emulate_ctxt *ctxt)
static int em_cr_write(struct x86_emulate_ctxt *ctxt)
{
- if (ctxt->ops->set_cr(ctxt, ctxt->modrm_reg, ctxt->src.val))
+ if (ctxt->ops->set_cr(ctxt, ctxt->modrm_reg, ctxt->src.val, false))
return emulate_gp(ctxt, 0);
/* Disable writeback. */
@@ -3766,7 +3767,7 @@ static int em_clts(struct x86_emulate_ctxt *ctxt)
cr0 = ctxt->ops->get_cr(ctxt, 0);
cr0 &= ~X86_CR0_TS;
- ctxt->ops->set_cr(ctxt, 0, cr0);
+ ctxt->ops->set_cr(ctxt, 0, cr0, false);
return X86EMUL_CONTINUE;
}
@@ -3866,7 +3867,7 @@ static int em_smsw(struct x86_emulate_ctxt *ctxt)
static int em_lmsw(struct x86_emulate_ctxt *ctxt)
{
ctxt->ops->set_cr(ctxt, 0, (ctxt->ops->get_cr(ctxt, 0) & ~0x0eul)
- | (ctxt->src.val & 0x0f));
+ | (ctxt->src.val & 0x0f), false);
ctxt->dst.type = OP_NONE;
return X86EMUL_CONTINUE;
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a419656521b6..f2745e3170b6 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5739,7 +5739,8 @@ static unsigned long emulator_get_cr(struct x86_emulate_ctxt *ctxt, int cr)
return value;
}
-static int emulator_set_cr(struct x86_emulate_ctxt *ctxt, int cr, ulong val)
+static int emulator_set_cr(struct x86_emulate_ctxt *ctxt, int cr, ulong val,
+ bool from_rsm)
{
struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
int res = 0;
@@ -5755,7 +5756,16 @@ static int emulator_set_cr(struct x86_emulate_ctxt *ctxt, int cr, ulong val)
res = kvm_set_cr3(vcpu, val);
break;
case 4:
+ /*
+ * set_cr4() may forbid to set certain flags (e.g. VMXE) from
+ * SMM but we're actually leaving it; temporary drop HF_SMM_MASK
+ * when setting CR4.
+ */
+ if (from_rsm)
+ vcpu->arch.hflags &= ~HF_SMM_MASK;
res = kvm_set_cr4(vcpu, mk_cr_64(kvm_read_cr4(vcpu), val));
+ if (from_rsm)
+ vcpu->arch.hflags |= HF_SMM_MASK;
break;
case 8:
res = kvm_set_cr8(vcpu, val);
--
2.20.1
^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH] KVM: x86: nVMX: allow RSM to restore VMXE CR4 flag
2019-03-26 13:07 [PATCH] KVM: x86: nVMX: allow RSM to restore VMXE CR4 flag Vitaly Kuznetsov
@ 2019-03-26 13:11 ` Liran Alon
2019-03-26 13:48 ` Vitaly Kuznetsov
[not found] ` <20190327192946.19128-1-sean.j.christopherson@intel.com>
1 sibling, 1 reply; 10+ messages in thread
From: Liran Alon @ 2019-03-26 13:11 UTC (permalink / raw)
To: Vitaly Kuznetsov
Cc: kvm, Paolo Bonzini, Radim Krčmář,
Jon Doron, Sean Christopherson, linux-kernel
> On 26 Mar 2019, at 15:07, Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>
> Commit 5bea5123cbf0 ("KVM: VMX: check nested state and CR4.VMXE against
> SMM") introduced a check to vmx_set_cr4() forbidding to set VMXE from SMM.
> The check is correct, however, there is a special case when RSM is called
> to leave SMM: rsm_enter_protected_mode() is called with HF_SMM_MASK still
> set and in case VMXE was set before entering SMM we're failing to return.
>
> Resolve the issue by temporary dropping HF_SMM_MASK around set_cr4() calls
> when ops->set_cr() is called from RSM.
>
> Reported-by: Jon Doron <arilou@gmail.com>
> Suggested-by: Liran Alon <liran.alon@oracle.com>
> Fixes: 5bea5123cbf0 ("KVM: VMX: check nested state and CR4.VMXE against SMM")
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Patch looks good to me.
Reviewed-by: Liran Alon <liran.alon@oracle.com>
> ---
> - Instread of putting the temporary HF_SMM_MASK drop to
> rsm_enter_protected_mode() (as was suggested by Liran), move it to
> emulator_set_cr() modifying its interface. emulate.c seems to be
> vcpu-specifics-free at this moment, we may want to keep it this way.
> - It seems that Hyper-V+UEFI on KVM is still broken, I'm observing sporadic
> hangs even with this patch. These hangs, however, seem to be unrelated to
> rsm.
Feel free to share details on these hangs ;)
Great work,
-Liran
> ---
> arch/x86/include/asm/kvm_emulate.h | 3 ++-
> arch/x86/kvm/emulate.c | 27 ++++++++++++++-------------
> arch/x86/kvm/x86.c | 12 +++++++++++-
> 3 files changed, 27 insertions(+), 15 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
> index 93c4bf598fb0..6c33caa82fa5 100644
> --- a/arch/x86/include/asm/kvm_emulate.h
> +++ b/arch/x86/include/asm/kvm_emulate.h
> @@ -203,7 +203,8 @@ struct x86_emulate_ops {
> void (*set_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
> void (*set_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
> ulong (*get_cr)(struct x86_emulate_ctxt *ctxt, int cr);
> - int (*set_cr)(struct x86_emulate_ctxt *ctxt, int cr, ulong val);
> + int (*set_cr)(struct x86_emulate_ctxt *ctxt, int cr, ulong val,
> + bool from_rsm);
> int (*cpl)(struct x86_emulate_ctxt *ctxt);
> int (*get_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong *dest);
> int (*set_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong value);
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index c338984c850d..a6204105d4d7 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -2413,7 +2413,7 @@ static int rsm_enter_protected_mode(struct x86_emulate_ctxt *ctxt,
> cr3 &= ~0xfff;
> }
>
> - bad = ctxt->ops->set_cr(ctxt, 3, cr3);
> + bad = ctxt->ops->set_cr(ctxt, 3, cr3, true);
> if (bad)
> return X86EMUL_UNHANDLEABLE;
>
> @@ -2422,20 +2422,20 @@ static int rsm_enter_protected_mode(struct x86_emulate_ctxt *ctxt,
> * Then enable protected mode. However, PCID cannot be enabled
> * if EFER.LMA=0, so set it separately.
> */
> - bad = ctxt->ops->set_cr(ctxt, 4, cr4 & ~X86_CR4_PCIDE);
> + bad = ctxt->ops->set_cr(ctxt, 4, cr4 & ~X86_CR4_PCIDE, true);
> if (bad)
> return X86EMUL_UNHANDLEABLE;
>
> - bad = ctxt->ops->set_cr(ctxt, 0, cr0);
> + bad = ctxt->ops->set_cr(ctxt, 0, cr0, true);
> if (bad)
> return X86EMUL_UNHANDLEABLE;
>
> if (cr4 & X86_CR4_PCIDE) {
> - bad = ctxt->ops->set_cr(ctxt, 4, cr4);
> + bad = ctxt->ops->set_cr(ctxt, 4, cr4, true);
> if (bad)
> return X86EMUL_UNHANDLEABLE;
> if (pcid) {
> - bad = ctxt->ops->set_cr(ctxt, 3, cr3 | pcid);
> + bad = ctxt->ops->set_cr(ctxt, 3, cr3 | pcid, true);
> if (bad)
> return X86EMUL_UNHANDLEABLE;
> }
> @@ -2581,7 +2581,7 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt)
>
> /* Zero CR4.PCIDE before CR0.PG. */
> if (cr4 & X86_CR4_PCIDE) {
> - ctxt->ops->set_cr(ctxt, 4, cr4 & ~X86_CR4_PCIDE);
> + ctxt->ops->set_cr(ctxt, 4, cr4 & ~X86_CR4_PCIDE, true);
> cr4 &= ~X86_CR4_PCIDE;
> }
>
> @@ -2595,11 +2595,12 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt)
> /* For the 64-bit case, this will clear EFER.LMA. */
> cr0 = ctxt->ops->get_cr(ctxt, 0);
> if (cr0 & X86_CR0_PE)
> - ctxt->ops->set_cr(ctxt, 0, cr0 & ~(X86_CR0_PG | X86_CR0_PE));
> + ctxt->ops->set_cr(ctxt, 0, cr0 & ~(X86_CR0_PG | X86_CR0_PE),
> + true);
>
> /* Now clear CR4.PAE (which must be done before clearing EFER.LME). */
> if (cr4 & X86_CR4_PAE)
> - ctxt->ops->set_cr(ctxt, 4, cr4 & ~X86_CR4_PAE);
> + ctxt->ops->set_cr(ctxt, 4, cr4 & ~X86_CR4_PAE, true);
>
> /* And finally go back to 32-bit mode. */
> efer = 0;
> @@ -3131,7 +3132,7 @@ static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt,
> int ret;
> u8 cpl;
>
> - if (ctxt->ops->set_cr(ctxt, 3, tss->cr3))
> + if (ctxt->ops->set_cr(ctxt, 3, tss->cr3, false))
> return emulate_gp(ctxt, 0);
> ctxt->_eip = tss->eip;
> ctxt->eflags = tss->eflags | 2;
> @@ -3331,7 +3332,7 @@ static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt,
> write_segment_descriptor(ctxt, tss_selector, &next_tss_desc);
> }
>
> - ops->set_cr(ctxt, 0, ops->get_cr(ctxt, 0) | X86_CR0_TS);
> + ops->set_cr(ctxt, 0, ops->get_cr(ctxt, 0) | X86_CR0_TS, false);
> ops->set_segment(ctxt, tss_selector, &next_tss_desc, 0, VCPU_SREG_TR);
>
> if (has_error_code) {
> @@ -3633,7 +3634,7 @@ static int em_movbe(struct x86_emulate_ctxt *ctxt)
>
> static int em_cr_write(struct x86_emulate_ctxt *ctxt)
> {
> - if (ctxt->ops->set_cr(ctxt, ctxt->modrm_reg, ctxt->src.val))
> + if (ctxt->ops->set_cr(ctxt, ctxt->modrm_reg, ctxt->src.val, false))
> return emulate_gp(ctxt, 0);
>
> /* Disable writeback. */
> @@ -3766,7 +3767,7 @@ static int em_clts(struct x86_emulate_ctxt *ctxt)
>
> cr0 = ctxt->ops->get_cr(ctxt, 0);
> cr0 &= ~X86_CR0_TS;
> - ctxt->ops->set_cr(ctxt, 0, cr0);
> + ctxt->ops->set_cr(ctxt, 0, cr0, false);
> return X86EMUL_CONTINUE;
> }
>
> @@ -3866,7 +3867,7 @@ static int em_smsw(struct x86_emulate_ctxt *ctxt)
> static int em_lmsw(struct x86_emulate_ctxt *ctxt)
> {
> ctxt->ops->set_cr(ctxt, 0, (ctxt->ops->get_cr(ctxt, 0) & ~0x0eul)
> - | (ctxt->src.val & 0x0f));
> + | (ctxt->src.val & 0x0f), false);
> ctxt->dst.type = OP_NONE;
> return X86EMUL_CONTINUE;
> }
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index a419656521b6..f2745e3170b6 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -5739,7 +5739,8 @@ static unsigned long emulator_get_cr(struct x86_emulate_ctxt *ctxt, int cr)
> return value;
> }
>
> -static int emulator_set_cr(struct x86_emulate_ctxt *ctxt, int cr, ulong val)
> +static int emulator_set_cr(struct x86_emulate_ctxt *ctxt, int cr, ulong val,
> + bool from_rsm)
> {
> struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
> int res = 0;
> @@ -5755,7 +5756,16 @@ static int emulator_set_cr(struct x86_emulate_ctxt *ctxt, int cr, ulong val)
> res = kvm_set_cr3(vcpu, val);
> break;
> case 4:
> + /*
> + * set_cr4() may forbid to set certain flags (e.g. VMXE) from
> + * SMM but we're actually leaving it; temporary drop HF_SMM_MASK
> + * when setting CR4.
> + */
> + if (from_rsm)
> + vcpu->arch.hflags &= ~HF_SMM_MASK;
> res = kvm_set_cr4(vcpu, mk_cr_64(kvm_read_cr4(vcpu), val));
> + if (from_rsm)
> + vcpu->arch.hflags |= HF_SMM_MASK;
> break;
> case 8:
> res = kvm_set_cr8(vcpu, val);
> --
> 2.20.1
>
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] KVM: x86: nVMX: allow RSM to restore VMXE CR4 flag
2019-03-26 13:11 ` Liran Alon
@ 2019-03-26 13:48 ` Vitaly Kuznetsov
2019-03-26 15:02 ` Liran Alon
0 siblings, 1 reply; 10+ messages in thread
From: Vitaly Kuznetsov @ 2019-03-26 13:48 UTC (permalink / raw)
To: Liran Alon
Cc: kvm, Paolo Bonzini, Radim Krčmář,
Jon Doron, Sean Christopherson, linux-kernel
Liran Alon <liran.alon@oracle.com> writes:
>> On 26 Mar 2019, at 15:07, Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>>
>> Commit 5bea5123cbf0 ("KVM: VMX: check nested state and CR4.VMXE against
>> SMM") introduced a check to vmx_set_cr4() forbidding to set VMXE from SMM.
>> The check is correct, however, there is a special case when RSM is called
>> to leave SMM: rsm_enter_protected_mode() is called with HF_SMM_MASK still
>> set and in case VMXE was set before entering SMM we're failing to return.
>>
>> Resolve the issue by temporary dropping HF_SMM_MASK around set_cr4() calls
>> when ops->set_cr() is called from RSM.
>>
>> Reported-by: Jon Doron <arilou@gmail.com>
>> Suggested-by: Liran Alon <liran.alon@oracle.com>
>> Fixes: 5bea5123cbf0 ("KVM: VMX: check nested state and CR4.VMXE against SMM")
>> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
>
> Patch looks good to me.
> Reviewed-by: Liran Alon <liran.alon@oracle.com>
Thanks!
>
>> ---
>> - Instread of putting the temporary HF_SMM_MASK drop to
>> rsm_enter_protected_mode() (as was suggested by Liran), move it to
>> emulator_set_cr() modifying its interface. emulate.c seems to be
>> vcpu-specifics-free at this moment, we may want to keep it this way.
>> - It seems that Hyper-V+UEFI on KVM is still broken, I'm observing sporadic
>> hangs even with this patch. These hangs, however, seem to be unrelated to
>> rsm.
>
> Feel free to share details on these hangs ;)
>
You've asked for it)
The immediate issue I'm observing is some sort of a lockup which is easy
to trigger with e.g. "-usb -device usb-tablet" on Qemu command line; it
seems we get too many interrupts and combined with preemtion timer for
L2 we're not making any progress:
kvm_userspace_exit: reason KVM_EXIT_IOAPIC_EOI (26)
kvm_set_irq: gsi 18 level 1 source 0
kvm_msi_set_irq: dst 0 vec 177 (Fixed|physical|level)
kvm_apic_accept_irq: apicid 0 vec 177 (Fixed|edge)
kvm_fpu: load
kvm_entry: vcpu 0
kvm_exit: reason VMRESUME rip 0xfffff80000848115 info 0 0
kvm_entry: vcpu 0
kvm_exit: reason PREEMPTION_TIMER rip 0xfffff800f4448e01 info 0 0
kvm_nested_vmexit: rip fffff800f4448e01 reason PREEMPTION_TIMER info1 0 info2 0 int_info 0 int_info_err 0
kvm_nested_vmexit_inject: reason EXTERNAL_INTERRUPT info1 0 info2 0 int_info 800000b1 int_info_err 0
kvm_entry: vcpu 0
kvm_exit: reason APIC_ACCESS rip 0xfffff8000081fe11 info 10b0 0
kvm_apic: apic_write APIC_EOI = 0x0
kvm_eoi: apicid 0 vector 177
kvm_fpu: unload
kvm_userspace_exit: reason KVM_EXIT_IOAPIC_EOI (26)
...
(and the pattern repeats)
Maybe it is a usb-only/Qemu-only problem, maybe not.
--
Vitaly
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] KVM: x86: nVMX: allow RSM to restore VMXE CR4 flag
2019-03-26 13:48 ` Vitaly Kuznetsov
@ 2019-03-26 15:02 ` Liran Alon
2019-03-27 10:08 ` Vitaly Kuznetsov
0 siblings, 1 reply; 10+ messages in thread
From: Liran Alon @ 2019-03-26 15:02 UTC (permalink / raw)
To: Vitaly Kuznetsov
Cc: kvm, Paolo Bonzini, Radim Krčmář,
Jon Doron, Sean Christopherson, linux-kernel
> On 26 Mar 2019, at 15:48, Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>
> Liran Alon <liran.alon@oracle.com> writes:
>
>>> On 26 Mar 2019, at 15:07, Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>>> - Instread of putting the temporary HF_SMM_MASK drop to
>>> rsm_enter_protected_mode() (as was suggested by Liran), move it to
>>> emulator_set_cr() modifying its interface. emulate.c seems to be
>>> vcpu-specifics-free at this moment, we may want to keep it this way.
>>> - It seems that Hyper-V+UEFI on KVM is still broken, I'm observing sporadic
>>> hangs even with this patch. These hangs, however, seem to be unrelated to
>>> rsm.
>>
>> Feel free to share details on these hangs ;)
>>
>
> You've asked for it)
>
> The immediate issue I'm observing is some sort of a lockup which is easy
> to trigger with e.g. "-usb -device usb-tablet" on Qemu command line; it
> seems we get too many interrupts and combined with preemtion timer for
> L2 we're not making any progress:
>
> kvm_userspace_exit: reason KVM_EXIT_IOAPIC_EOI (26)
> kvm_set_irq: gsi 18 level 1 source 0
> kvm_msi_set_irq: dst 0 vec 177 (Fixed|physical|level)
> kvm_apic_accept_irq: apicid 0 vec 177 (Fixed|edge)
> kvm_fpu: load
> kvm_entry: vcpu 0
> kvm_exit: reason VMRESUME rip 0xfffff80000848115 info 0 0
> kvm_entry: vcpu 0
> kvm_exit: reason PREEMPTION_TIMER rip 0xfffff800f4448e01 info 0 0
> kvm_nested_vmexit: rip fffff800f4448e01 reason PREEMPTION_TIMER info1 0 info2 0 int_info 0 int_info_err 0
> kvm_nested_vmexit_inject: reason EXTERNAL_INTERRUPT info1 0 info2 0 int_info 800000b1 int_info_err 0
> kvm_entry: vcpu 0
> kvm_exit: reason APIC_ACCESS rip 0xfffff8000081fe11 info 10b0 0
> kvm_apic: apic_write APIC_EOI = 0x0
> kvm_eoi: apicid 0 vector 177
> kvm_fpu: unload
> kvm_userspace_exit: reason KVM_EXIT_IOAPIC_EOI (26)
> ...
> (and the pattern repeats)
>
> Maybe it is a usb-only/Qemu-only problem, maybe not.
>
> --
> Vitaly
The trace of kvm_apic_accept_irq should indicate that __apic_accept_irq() was called to inject an interrupt to L1 guest.
(I know that now we are running in L1 because next exit is a VMRESUME).
However, it is surprising to see that on next entry to guest, no interrupt was injected by vmx_inject_irq().
It may be because L1 guest is currently running with interrupt disabled and therefore only an IRQ-window was requested.
(Too bad we don’t have a trace for this…)
Next, we got an exit from L1 guest on VMRESUME. As part of it’s handling, active VMCS was changed from vmcs01 to vmcs02.
I believe the immediate exit later on preemption-timer was because the immediate-exit-request mechanism was invoked
which is now implemented by setting a VMX preemption-timer with value of 0 (Thanks to Sean).
(See vmx_vcpu_run() -> vmx_update_hv_timer() -> vmx_arm_hv_timer(vmx, 0)).
(Note that the pending interrupt was evaluated because of a recent patch of mine to nested_vmx_enter_non_root_mode()
to request KVM_REQ_EVENT when vmcs01 have requested an IRQ-window)
Therefore when entering L2, you immediately get an exit on PREEMPTION_TIMER which will cause eventually L0 to call
vmx_check_nested_events() which notices now the pending interrupt that should have been injected before to L1
and now exit from L2 to L1 on EXTERNAL_INTERRUPT on vector 0xb1.
Then L1 handles the interrupt by performing an EOI to LAPIC which propagate an EOI to IOAPIC which immediately re-inject
the interrupt (after clearing the remote_irr) as the irq-line is still set. i.e. QEMU’s ioapic_eoi_broadcast() calls ioapic_service() immediate after it clears remote-irr for this pin.
Also note that in trace we see only a single kvm_set_irq to level 1 but we don’t see immediately another kvm_set_irq to level 0.
This should indicate that in QEMU’s IOAPIC redirection-table, this pin is configured as level-triggered interrupt.
However, the trace of kvm_apic_accept_irq indicates that this interrupt is raised as an edge-triggered interrupt.
To sum up:
1) I would create a patch to add a trace to vcpu_enter_guest() when calling enable_smi_window() / enable_nmi_window() / enable_irq_window().
2) It is worth investigating why MSI trigger-mode is edge-triggered instead of level-triggered.
3) If this is indeed a level-triggered interrupt, it is worth investigating how the interrupt source behaves. i.e. What cause this device to lower the irq-line?
(As we don’t see any I/O Port or MMIO access by L1 guest interrupt-handler before performing the EOI)
4) Does this issue reproduce also when running with kernel-irqchip? (Instead of split-irqchip)
-Liran
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] KVM: x86: nVMX: allow RSM to restore VMXE CR4 flag
2019-03-26 15:02 ` Liran Alon
@ 2019-03-27 10:08 ` Vitaly Kuznetsov
0 siblings, 0 replies; 10+ messages in thread
From: Vitaly Kuznetsov @ 2019-03-27 10:08 UTC (permalink / raw)
To: Liran Alon
Cc: kvm, Paolo Bonzini, Radim Krčmář,
Jon Doron, Sean Christopherson, linux-kernel
Liran Alon <liran.alon@oracle.com> writes:
>> On 26 Mar 2019, at 15:48, Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>>
>> Liran Alon <liran.alon@oracle.com> writes:
>>
>>>> On 26 Mar 2019, at 15:07, Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>>>> - Instread of putting the temporary HF_SMM_MASK drop to
>>>> rsm_enter_protected_mode() (as was suggested by Liran), move it to
>>>> emulator_set_cr() modifying its interface. emulate.c seems to be
>>>> vcpu-specifics-free at this moment, we may want to keep it this way.
>>>> - It seems that Hyper-V+UEFI on KVM is still broken, I'm observing sporadic
>>>> hangs even with this patch. These hangs, however, seem to be unrelated to
>>>> rsm.
>>>
>>> Feel free to share details on these hangs ;)
>>>
>>
>> You've asked for it)
>>
>> The immediate issue I'm observing is some sort of a lockup which is easy
>> to trigger with e.g. "-usb -device usb-tablet" on Qemu command line; it
>> seems we get too many interrupts and combined with preemtion timer for
>> L2 we're not making any progress:
>>
>> kvm_userspace_exit: reason KVM_EXIT_IOAPIC_EOI (26)
>> kvm_set_irq: gsi 18 level 1 source 0
>> kvm_msi_set_irq: dst 0 vec 177 (Fixed|physical|level)
>> kvm_apic_accept_irq: apicid 0 vec 177 (Fixed|edge)
>> kvm_fpu: load
>> kvm_entry: vcpu 0
>> kvm_exit: reason VMRESUME rip 0xfffff80000848115 info 0 0
>> kvm_entry: vcpu 0
>> kvm_exit: reason PREEMPTION_TIMER rip 0xfffff800f4448e01 info 0 0
>> kvm_nested_vmexit: rip fffff800f4448e01 reason PREEMPTION_TIMER info1 0 info2 0 int_info 0 int_info_err 0
>> kvm_nested_vmexit_inject: reason EXTERNAL_INTERRUPT info1 0 info2 0 int_info 800000b1 int_info_err 0
>> kvm_entry: vcpu 0
>> kvm_exit: reason APIC_ACCESS rip 0xfffff8000081fe11 info 10b0 0
>> kvm_apic: apic_write APIC_EOI = 0x0
>> kvm_eoi: apicid 0 vector 177
>> kvm_fpu: unload
>> kvm_userspace_exit: reason KVM_EXIT_IOAPIC_EOI (26)
>> ...
>> (and the pattern repeats)
>>
>> Maybe it is a usb-only/Qemu-only problem, maybe not.
>>
>> --
>> Vitaly
>
> The trace of kvm_apic_accept_irq should indicate that __apic_accept_irq() was called to inject an interrupt to L1 guest.
> (I know that now we are running in L1 because next exit is a VMRESUME).
>
> However, it is surprising to see that on next entry to guest, no interrupt was injected by vmx_inject_irq().
> It may be because L1 guest is currently running with interrupt disabled and therefore only an IRQ-window was requested.
> (Too bad we don’t have a trace for this…)
>
> Next, we got an exit from L1 guest on VMRESUME. As part of it’s handling, active VMCS was changed from vmcs01 to vmcs02.
> I believe the immediate exit later on preemption-timer was because the immediate-exit-request mechanism was invoked
> which is now implemented by setting a VMX preemption-timer with value of 0 (Thanks to Sean).
> (See vmx_vcpu_run() -> vmx_update_hv_timer() -> vmx_arm_hv_timer(vmx, 0)).
> (Note that the pending interrupt was evaluated because of a recent patch of mine to nested_vmx_enter_non_root_mode()
> to request KVM_REQ_EVENT when vmcs01 have requested an IRQ-window)
>
> Therefore when entering L2, you immediately get an exit on PREEMPTION_TIMER which will cause eventually L0 to call
> vmx_check_nested_events() which notices now the pending interrupt that should have been injected before to L1
> and now exit from L2 to L1 on EXTERNAL_INTERRUPT on vector 0xb1.
>
> Then L1 handles the interrupt by performing an EOI to LAPIC which propagate an EOI to IOAPIC which immediately re-inject
> the interrupt (after clearing the remote_irr) as the irq-line is still set. i.e. QEMU’s ioapic_eoi_broadcast() calls ioapic_service() immediate after it clears remote-irr for this pin.
>
> Also note that in trace we see only a single kvm_set_irq to level 1 but we don’t see immediately another kvm_set_irq to level 0.
> This should indicate that in QEMU’s IOAPIC redirection-table, this pin is configured as level-triggered interrupt.
> However, the trace of kvm_apic_accept_irq indicates that this interrupt is raised as an edge-triggered interrupt.
>
> To sum up:
> 1) I would create a patch to add a trace to vcpu_enter_guest() when calling enable_smi_window() / enable_nmi_window() / enable_irq_window().
> 2) It is worth investigating why MSI trigger-mode is edge-triggered instead of level-triggered.
> 3) If this is indeed a level-triggered interrupt, it is worth investigating how the interrupt source behaves. i.e. What cause this device to lower the irq-line?
> (As we don’t see any I/O Port or MMIO access by L1 guest interrupt-handler before performing the EOI)
> 4) Does this issue reproduce also when running with kernel-irqchip? (Instead of split-irqchip)
>
Thank you Liran,
all are valuable suggestions. It seems the isssue doesn't reproduce with
'kernel-irqchip=on' but reproduces with "kernel-irqchip=split". My first
guess would then be that we're less picky with in-kernel implementation
about the observed edge/level discrepancy. I'll be investigating and
share my findings.
--
Vitaly
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] KVM: x86: nVMX: allow RSM to restore VMXE CR4 flag
[not found] ` <CALMp9eQPwFy5GvjDbE9wQQYEDdYfHzEwm6n1XZgQ_hCuk9vp+Q@mail.gmail.com>
@ 2019-04-09 8:21 ` Vitaly Kuznetsov
2019-04-09 16:31 ` Paolo Bonzini
0 siblings, 1 reply; 10+ messages in thread
From: Vitaly Kuznetsov @ 2019-04-09 8:21 UTC (permalink / raw)
To: kvm list
Cc: Sean Christopherson, Paolo Bonzini, Radim Krčmář,
Joerg Roedel, Jon Doron, Liran Alon, Jim Mattson
Jim Mattson <jmattson@google.com> writes:
> On Thu, Mar 28, 2019 at 1:56 AM Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>
>> P.S. We probably need a kvm-unit-tests or selftests test as
>> Hyper-V+secureboot is the only known way to test this atm.
>
> Yes, please! And the requirement for providing tests of new features
> should be applied universally, rather than ad hoc.
FWIW, I have a working proof-of-concept test for KVM selftests doing
SMI/RSM. I'm going to clean it up, enhance a bit, maybe add something to
state_test and send out (unless someone beats me up to it, of course :-)
--
Vitaly
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] KVM: x86: nVMX: allow RSM to restore VMXE CR4 flag
2019-04-09 8:21 ` Vitaly Kuznetsov
@ 2019-04-09 16:31 ` Paolo Bonzini
2019-04-10 9:38 ` [RFC] selftests: kvm: add a selftest for SMM Vitaly Kuznetsov
0 siblings, 1 reply; 10+ messages in thread
From: Paolo Bonzini @ 2019-04-09 16:31 UTC (permalink / raw)
To: Vitaly Kuznetsov, kvm list
Cc: Sean Christopherson, Radim Krčmář,
Joerg Roedel, Jon Doron, Liran Alon, Jim Mattson
On 09/04/19 10:21, Vitaly Kuznetsov wrote:
> Jim Mattson <jmattson@google.com> writes:
>
>> On Thu, Mar 28, 2019 at 1:56 AM Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>>
>>> P.S. We probably need a kvm-unit-tests or selftests test as
>>> Hyper-V+secureboot is the only known way to test this atm.
>>
>> Yes, please! And the requirement for providing tests of new features
>> should be applied universally, rather than ad hoc.
>
> FWIW, I have a working proof-of-concept test for KVM selftests doing
> SMI/RSM. I'm going to clean it up, enhance a bit, maybe add something to
> state_test and send out (unless someone beats me up to it, of course :-)
Oh, me too. :) But please send yours, and then we'll see what can be
taken from mine. state_test can come later.
Paolo
^ permalink raw reply [flat|nested] 10+ messages in thread
* [RFC] selftests: kvm: add a selftest for SMM
2019-04-09 16:31 ` Paolo Bonzini
@ 2019-04-10 9:38 ` Vitaly Kuznetsov
2019-04-10 10:10 ` Paolo Bonzini
0 siblings, 1 reply; 10+ messages in thread
From: Vitaly Kuznetsov @ 2019-04-10 9:38 UTC (permalink / raw)
To: kvm
Cc: Paolo Bonzini, Radim Krčmář,
Liran Alon, Sean Christopherson, Jim Mattson, linux-kernel
Early RFC, based on state_test.
Add a simplistic test for SMM. Currently it fails with
"Unexpected result from KVM_SET_NESTED_STATE" even when a patch fixing
rsm after VMXON is added. There's likey some other issue in nested
save/restore when SMM os on.
The test implements its own sync between the guest and the host as using
our ucall library seems to be too cumbersome: SMI handler is happening in
real-address mode.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/include/x86_64/processor.h | 27 +++
tools/testing/selftests/kvm/x86_64/smm_test.c | 159 ++++++++++++++++++
3 files changed, 187 insertions(+)
create mode 100644 tools/testing/selftests/kvm/x86_64/smm_test.c
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 3c1f4bdf9000..257955593cdf 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -17,6 +17,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/state_test
TEST_GEN_PROGS_x86_64 += x86_64/evmcs_test
TEST_GEN_PROGS_x86_64 += x86_64/hyperv_cpuid
TEST_GEN_PROGS_x86_64 += x86_64/vmx_close_while_nested_test
+TEST_GEN_PROGS_x86_64 += x86_64/smm_test
TEST_GEN_PROGS_x86_64 += dirty_log_test
TEST_GEN_PROGS_x86_64 += clear_dirty_log_test
diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index e2884c2b81ff..6063d5b2f356 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -778,6 +778,33 @@ void vcpu_set_msr(struct kvm_vm *vm, uint32_t vcpuid, uint64_t msr_index,
#define MSR_IA32_APICBASE_ENABLE (1<<11)
#define MSR_IA32_APICBASE_BASE (0xfffff<<12)
+#define APIC_BASE_MSR 0x800
+#define X2APIC_ENABLE (1UL << 10)
+#define APIC_ICR 0x300
+#define APIC_DEST_SELF 0x40000
+#define APIC_DEST_ALLINC 0x80000
+#define APIC_DEST_ALLBUT 0xC0000
+#define APIC_ICR_RR_MASK 0x30000
+#define APIC_ICR_RR_INVALID 0x00000
+#define APIC_ICR_RR_INPROG 0x10000
+#define APIC_ICR_RR_VALID 0x20000
+#define APIC_INT_LEVELTRIG 0x08000
+#define APIC_INT_ASSERT 0x04000
+#define APIC_ICR_BUSY 0x01000
+#define APIC_DEST_LOGICAL 0x00800
+#define APIC_DEST_PHYSICAL 0x00000
+#define APIC_DM_FIXED 0x00000
+#define APIC_DM_FIXED_MASK 0x00700
+#define APIC_DM_LOWEST 0x00100
+#define APIC_DM_SMI 0x00200
+#define APIC_DM_REMRD 0x00300
+#define APIC_DM_NMI 0x00400
+#define APIC_DM_INIT 0x00500
+#define APIC_DM_STARTUP 0x00600
+#define APIC_DM_EXTINT 0x00700
+#define APIC_VECTOR_MASK 0x000FF
+#define APIC_ICR2 0x310
+
#define MSR_IA32_TSCDEADLINE 0x000006e0
#define MSR_IA32_UCODE_WRITE 0x00000079
diff --git a/tools/testing/selftests/kvm/x86_64/smm_test.c b/tools/testing/selftests/kvm/x86_64/smm_test.c
new file mode 100644
index 000000000000..3452b592588a
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/smm_test.c
@@ -0,0 +1,159 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018, Red Hat, Inc.
+ *
+ * Tests for SMM.
+ */
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <sys/ioctl.h>
+
+#include "test_util.h"
+
+#include "kvm_util.h"
+
+#include "vmx.h"
+
+#define VCPU_ID 1
+
+#define PAGE_SIZE 4096
+
+#define SMRAM_SIZE (16 * PAGE_SIZE)
+#define SMRAM_GPA 0x1000000
+#define SMRAM_STAGE 0xfe
+
+#define STR(x) #x
+#define XSTR(s) STR(s)
+
+#define SYNC_PORT 0xe
+#define DONE 0xff
+
+/*
+ * This is compiled as normal 64-bit code, however, SMI handler is executed
+ * in real-address mode. To stay simple we're limiting ourselves to a mode
+ * independent subset of asm here.
+ * SMI handler always report back fixed stage SMRAM_STAGE.
+ */
+void smi_handler(void)
+{
+ asm volatile("mov $" XSTR(SMRAM_STAGE) ", %al \n"
+ "in $" XSTR(SYNC_PORT) ", %al \n"
+ "rsm \n");
+}
+/* This should change if the code above changes in length */
+#define SMI_HANDLER_SIZE 6
+
+void sync_with_host(uint64_t phase)
+{
+ asm volatile("in $" XSTR(SYNC_PORT)", %%al \n"
+ : : "a" (phase));
+}
+
+void self_smi(void)
+{
+ wrmsr(APIC_BASE_MSR + (APIC_ICR >> 4),
+ APIC_DEST_SELF | APIC_INT_ASSERT | APIC_DM_SMI);
+}
+
+void guest_code(struct vmx_pages *vmx_pages)
+{
+ uint64_t apicbase = rdmsr(MSR_IA32_APICBASE);
+
+ sync_with_host(1);
+
+ wrmsr(MSR_IA32_APICBASE, apicbase | X2APIC_ENABLE);
+
+ sync_with_host(2);
+
+ self_smi();
+
+ sync_with_host(4);
+
+ if (vmx_pages) {
+ GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
+
+ sync_with_host(5);
+
+ self_smi();
+
+ sync_with_host(7);
+ }
+
+ sync_with_host(DONE);
+}
+
+int main(int argc, char *argv[])
+{
+ struct vmx_pages *vmx_pages = NULL;
+ vm_vaddr_t vmx_pages_gva = 0;
+
+ struct kvm_regs regs;
+ struct kvm_vm *vm;
+ struct kvm_run *run;
+ struct kvm_x86_state *state;
+ int stage, stage_reported;
+
+ /* Create VM */
+ vm = vm_create_default(VCPU_ID, 0, guest_code);
+
+ vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
+
+ run = vcpu_state(vm, VCPU_ID);
+
+ vcpu_regs_get(vm, VCPU_ID, ®s);
+
+ vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, SMRAM_GPA,
+ 1 << 16 | 1, SMRAM_SIZE/PAGE_SIZE, 0);
+
+ memset(addr_gpa2hva(vm, SMRAM_GPA), 0x0, SMRAM_SIZE);
+ memcpy(addr_gpa2hva(vm, SMRAM_GPA) + 0x8000, smi_handler,
+ SMI_HANDLER_SIZE);
+
+ vcpu_set_msr(vm, VCPU_ID, MSR_IA32_SMBASE, SMRAM_GPA);
+
+ if (kvm_check_cap(KVM_CAP_NESTED_STATE)) {
+ vmx_pages = vcpu_alloc_vmx(vm, &vmx_pages_gva);
+ vcpu_args_set(vm, VCPU_ID, 1, vmx_pages_gva);
+ } else {
+ printf("will skip SMM test with VMX enabled\n");
+ vcpu_args_set(vm, VCPU_ID, 1, 0);
+ }
+
+ for (stage = 1;; stage++) {
+ _vcpu_run(vm, VCPU_ID);
+ TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
+ "Stage %d: unexpected exit reason: %u (%s),\n",
+ stage, run->exit_reason,
+ exit_reason_str(run->exit_reason));
+
+ memset(®s, 0, sizeof(regs));
+ vcpu_regs_get(vm, VCPU_ID, ®s);
+
+ stage_reported = regs.rax & 0xff;
+
+ if (stage_reported == DONE)
+ goto done;
+
+ TEST_ASSERT(stage_reported == stage ||
+ stage_reported == SMRAM_STAGE,
+ "Unexpected stage: #%x, got %x",
+ stage, stage_reported);
+
+ /* This piece of code needs sharing with state_test/evmcs_test */
+ state = vcpu_save_state(vm, VCPU_ID);
+ kvm_vm_release(vm);
+ kvm_vm_restart(vm, O_RDWR);
+ vm_vcpu_add(vm, VCPU_ID, 0, 0);
+ vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
+ vcpu_load_state(vm, VCPU_ID, state);
+ run = vcpu_state(vm, VCPU_ID);
+ free(state);
+ }
+
+done:
+ kvm_vm_free(vm);
+}
--
2.20.1
^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [RFC] selftests: kvm: add a selftest for SMM
2019-04-10 9:38 ` [RFC] selftests: kvm: add a selftest for SMM Vitaly Kuznetsov
@ 2019-04-10 10:10 ` Paolo Bonzini
2019-04-10 10:32 ` Vitaly Kuznetsov
0 siblings, 1 reply; 10+ messages in thread
From: Paolo Bonzini @ 2019-04-10 10:10 UTC (permalink / raw)
To: Vitaly Kuznetsov, kvm
Cc: Radim Krčmář,
Liran Alon, Sean Christopherson, Jim Mattson, linux-kernel
On 10/04/19 11:38, Vitaly Kuznetsov wrote:
> Early RFC, based on state_test.
>
> Add a simplistic test for SMM. Currently it fails with
> "Unexpected result from KVM_SET_NESTED_STATE" even when a patch fixing
> rsm after VMXON is added. There's likey some other issue in nested
> save/restore when SMM os on.
>
> The test implements its own sync between the guest and the host as using
> our ucall library seems to be too cumbersome: SMI handler is happening in
> real-address mode.
>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
> tools/testing/selftests/kvm/Makefile | 1 +
> .../selftests/kvm/include/x86_64/processor.h | 27 +++
> tools/testing/selftests/kvm/x86_64/smm_test.c | 159 ++++++++++++++++++
> 3 files changed, 187 insertions(+)
> create mode 100644 tools/testing/selftests/kvm/x86_64/smm_test.c
>
> diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
> index 3c1f4bdf9000..257955593cdf 100644
> --- a/tools/testing/selftests/kvm/Makefile
> +++ b/tools/testing/selftests/kvm/Makefile
> @@ -17,6 +17,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/state_test
> TEST_GEN_PROGS_x86_64 += x86_64/evmcs_test
> TEST_GEN_PROGS_x86_64 += x86_64/hyperv_cpuid
> TEST_GEN_PROGS_x86_64 += x86_64/vmx_close_while_nested_test
> +TEST_GEN_PROGS_x86_64 += x86_64/smm_test
> TEST_GEN_PROGS_x86_64 += dirty_log_test
> TEST_GEN_PROGS_x86_64 += clear_dirty_log_test
>
> diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
> index e2884c2b81ff..6063d5b2f356 100644
> --- a/tools/testing/selftests/kvm/include/x86_64/processor.h
> +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
> @@ -778,6 +778,33 @@ void vcpu_set_msr(struct kvm_vm *vm, uint32_t vcpuid, uint64_t msr_index,
> #define MSR_IA32_APICBASE_ENABLE (1<<11)
> #define MSR_IA32_APICBASE_BASE (0xfffff<<12)
>
> +#define APIC_BASE_MSR 0x800
> +#define X2APIC_ENABLE (1UL << 10)
> +#define APIC_ICR 0x300
> +#define APIC_DEST_SELF 0x40000
> +#define APIC_DEST_ALLINC 0x80000
> +#define APIC_DEST_ALLBUT 0xC0000
> +#define APIC_ICR_RR_MASK 0x30000
> +#define APIC_ICR_RR_INVALID 0x00000
> +#define APIC_ICR_RR_INPROG 0x10000
> +#define APIC_ICR_RR_VALID 0x20000
> +#define APIC_INT_LEVELTRIG 0x08000
> +#define APIC_INT_ASSERT 0x04000
> +#define APIC_ICR_BUSY 0x01000
> +#define APIC_DEST_LOGICAL 0x00800
> +#define APIC_DEST_PHYSICAL 0x00000
> +#define APIC_DM_FIXED 0x00000
> +#define APIC_DM_FIXED_MASK 0x00700
> +#define APIC_DM_LOWEST 0x00100
> +#define APIC_DM_SMI 0x00200
> +#define APIC_DM_REMRD 0x00300
> +#define APIC_DM_NMI 0x00400
> +#define APIC_DM_INIT 0x00500
> +#define APIC_DM_STARTUP 0x00600
> +#define APIC_DM_EXTINT 0x00700
> +#define APIC_VECTOR_MASK 0x000FF
> +#define APIC_ICR2 0x310
> +
> #define MSR_IA32_TSCDEADLINE 0x000006e0
>
> #define MSR_IA32_UCODE_WRITE 0x00000079
> diff --git a/tools/testing/selftests/kvm/x86_64/smm_test.c b/tools/testing/selftests/kvm/x86_64/smm_test.c
> new file mode 100644
> index 000000000000..3452b592588a
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/x86_64/smm_test.c
> @@ -0,0 +1,159 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2018, Red Hat, Inc.
> + *
> + * Tests for SMM.
> + */
> +#define _GNU_SOURCE /* for program_invocation_short_name */
> +#include <fcntl.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <stdint.h>
> +#include <string.h>
> +#include <sys/ioctl.h>
> +
> +#include "test_util.h"
> +
> +#include "kvm_util.h"
> +
> +#include "vmx.h"
> +
> +#define VCPU_ID 1
> +
> +#define PAGE_SIZE 4096
> +
> +#define SMRAM_SIZE (16 * PAGE_SIZE)
> +#define SMRAM_GPA 0x1000000
> +#define SMRAM_STAGE 0xfe
> +
> +#define STR(x) #x
> +#define XSTR(s) STR(s)
> +
> +#define SYNC_PORT 0xe
> +#define DONE 0xff
> +
> +/*
> + * This is compiled as normal 64-bit code, however, SMI handler is executed
> + * in real-address mode. To stay simple we're limiting ourselves to a mode
> + * independent subset of asm here.
> + * SMI handler always report back fixed stage SMRAM_STAGE.
> + */
> +void smi_handler(void)
> +{
> + asm volatile("mov $" XSTR(SMRAM_STAGE) ", %al \n"
> + "in $" XSTR(SYNC_PORT) ", %al \n"
> + "rsm \n");
> +}
> +/* This should change if the code above changes in length */
> +#define SMI_HANDLER_SIZE 6
Here I had similar code but I just wrote hex instead. :)
> +
> +void sync_with_host(uint64_t phase)
> +{
> + asm volatile("in $" XSTR(SYNC_PORT)", %%al \n"
> + : : "a" (phase));
> +}
> +
> +void self_smi(void)
> +{
> + wrmsr(APIC_BASE_MSR + (APIC_ICR >> 4),
> + APIC_DEST_SELF | APIC_INT_ASSERT | APIC_DM_SMI);
> +}
> +
> +void guest_code(struct vmx_pages *vmx_pages)
> +{
> + uint64_t apicbase = rdmsr(MSR_IA32_APICBASE);
> +
> + sync_with_host(1);
> +
> + wrmsr(MSR_IA32_APICBASE, apicbase | X2APIC_ENABLE);
> +
> + sync_with_host(2);
> +
> + self_smi();
> +
> + sync_with_host(4);
> +
> + if (vmx_pages) {
> + GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
> +
> + sync_with_host(5);
> +
> + self_smi();
> +
> + sync_with_host(7);
> + }
> +
> + sync_with_host(DONE);
> +}
> +
> +int main(int argc, char *argv[])
> +{
> + struct vmx_pages *vmx_pages = NULL;
> + vm_vaddr_t vmx_pages_gva = 0;
> +
> + struct kvm_regs regs;
> + struct kvm_vm *vm;
> + struct kvm_run *run;
> + struct kvm_x86_state *state;
> + int stage, stage_reported;
> +
> + /* Create VM */
> + vm = vm_create_default(VCPU_ID, 0, guest_code);
> +
> + vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
> +
> + run = vcpu_state(vm, VCPU_ID);
> +
> + vcpu_regs_get(vm, VCPU_ID, ®s);
Unused?
> +
> + vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, SMRAM_GPA,
> + 1 << 16 | 1, SMRAM_SIZE/PAGE_SIZE, 0);
Better add a vm_phy_pages_alloc here.
I'll debug the remaining failure and post it again.
Paolo
> + memset(addr_gpa2hva(vm, SMRAM_GPA), 0x0, SMRAM_SIZE);
> + memcpy(addr_gpa2hva(vm, SMRAM_GPA) + 0x8000, smi_handler,
> + SMI_HANDLER_SIZE);
> +
> + vcpu_set_msr(vm, VCPU_ID, MSR_IA32_SMBASE, SMRAM_GPA);
> +
> + if (kvm_check_cap(KVM_CAP_NESTED_STATE)) {
> + vmx_pages = vcpu_alloc_vmx(vm, &vmx_pages_gva);
> + vcpu_args_set(vm, VCPU_ID, 1, vmx_pages_gva);
> + } else {
> + printf("will skip SMM test with VMX enabled\n");
> + vcpu_args_set(vm, VCPU_ID, 1, 0);
> + }
> +
> + for (stage = 1;; stage++) {
> + _vcpu_run(vm, VCPU_ID);
> + TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
> + "Stage %d: unexpected exit reason: %u (%s),\n",
> + stage, run->exit_reason,
> + exit_reason_str(run->exit_reason));
> +
> + memset(®s, 0, sizeof(regs));
> + vcpu_regs_get(vm, VCPU_ID, ®s);
> +
> + stage_reported = regs.rax & 0xff;
> +
> + if (stage_reported == DONE)
> + goto done;
> +
> + TEST_ASSERT(stage_reported == stage ||
> + stage_reported == SMRAM_STAGE,
> + "Unexpected stage: #%x, got %x",
> + stage, stage_reported);
> +
> + /* This piece of code needs sharing with state_test/evmcs_test */
> + state = vcpu_save_state(vm, VCPU_ID);
> + kvm_vm_release(vm);
> + kvm_vm_restart(vm, O_RDWR);
> + vm_vcpu_add(vm, VCPU_ID, 0, 0);
> + vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
> + vcpu_load_state(vm, VCPU_ID, state);
> + run = vcpu_state(vm, VCPU_ID);
> + free(state);
> + }
> +
> +done:
> + kvm_vm_free(vm);
> +}
>
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [RFC] selftests: kvm: add a selftest for SMM
2019-04-10 10:10 ` Paolo Bonzini
@ 2019-04-10 10:32 ` Vitaly Kuznetsov
0 siblings, 0 replies; 10+ messages in thread
From: Vitaly Kuznetsov @ 2019-04-10 10:32 UTC (permalink / raw)
To: Paolo Bonzini, kvm
Cc: Radim Krčmář,
Liran Alon, Sean Christopherson, Jim Mattson, linux-kernel
Paolo Bonzini <pbonzini@redhat.com> writes:
> On 10/04/19 11:38, Vitaly Kuznetsov wrote:
>> Early RFC, based on state_test.
>>
>> Add a simplistic test for SMM. Currently it fails with
>> "Unexpected result from KVM_SET_NESTED_STATE" even when a patch fixing
>> rsm after VMXON is added. There's likey some other issue in nested
>> save/restore when SMM os on.
>>
>> The test implements its own sync between the guest and the host as using
>> our ucall library seems to be too cumbersome: SMI handler is happening in
>> real-address mode.
>>
>> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
>> ---
>> tools/testing/selftests/kvm/Makefile | 1 +
>> .../selftests/kvm/include/x86_64/processor.h | 27 +++
>> tools/testing/selftests/kvm/x86_64/smm_test.c | 159 ++++++++++++++++++
>> 3 files changed, 187 insertions(+)
>> create mode 100644 tools/testing/selftests/kvm/x86_64/smm_test.c
>>
>> diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
>> index 3c1f4bdf9000..257955593cdf 100644
>> --- a/tools/testing/selftests/kvm/Makefile
>> +++ b/tools/testing/selftests/kvm/Makefile
>> @@ -17,6 +17,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/state_test
>> TEST_GEN_PROGS_x86_64 += x86_64/evmcs_test
>> TEST_GEN_PROGS_x86_64 += x86_64/hyperv_cpuid
>> TEST_GEN_PROGS_x86_64 += x86_64/vmx_close_while_nested_test
>> +TEST_GEN_PROGS_x86_64 += x86_64/smm_test
>> TEST_GEN_PROGS_x86_64 += dirty_log_test
>> TEST_GEN_PROGS_x86_64 += clear_dirty_log_test
>>
>> diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
>> index e2884c2b81ff..6063d5b2f356 100644
>> --- a/tools/testing/selftests/kvm/include/x86_64/processor.h
>> +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
>> @@ -778,6 +778,33 @@ void vcpu_set_msr(struct kvm_vm *vm, uint32_t vcpuid, uint64_t msr_index,
>> #define MSR_IA32_APICBASE_ENABLE (1<<11)
>> #define MSR_IA32_APICBASE_BASE (0xfffff<<12)
>>
>> +#define APIC_BASE_MSR 0x800
>> +#define X2APIC_ENABLE (1UL << 10)
>> +#define APIC_ICR 0x300
>> +#define APIC_DEST_SELF 0x40000
>> +#define APIC_DEST_ALLINC 0x80000
>> +#define APIC_DEST_ALLBUT 0xC0000
>> +#define APIC_ICR_RR_MASK 0x30000
>> +#define APIC_ICR_RR_INVALID 0x00000
>> +#define APIC_ICR_RR_INPROG 0x10000
>> +#define APIC_ICR_RR_VALID 0x20000
>> +#define APIC_INT_LEVELTRIG 0x08000
>> +#define APIC_INT_ASSERT 0x04000
>> +#define APIC_ICR_BUSY 0x01000
>> +#define APIC_DEST_LOGICAL 0x00800
>> +#define APIC_DEST_PHYSICAL 0x00000
>> +#define APIC_DM_FIXED 0x00000
>> +#define APIC_DM_FIXED_MASK 0x00700
>> +#define APIC_DM_LOWEST 0x00100
>> +#define APIC_DM_SMI 0x00200
>> +#define APIC_DM_REMRD 0x00300
>> +#define APIC_DM_NMI 0x00400
>> +#define APIC_DM_INIT 0x00500
>> +#define APIC_DM_STARTUP 0x00600
>> +#define APIC_DM_EXTINT 0x00700
>> +#define APIC_VECTOR_MASK 0x000FF
>> +#define APIC_ICR2 0x310
>> +
>> #define MSR_IA32_TSCDEADLINE 0x000006e0
>>
>> #define MSR_IA32_UCODE_WRITE 0x00000079
>> diff --git a/tools/testing/selftests/kvm/x86_64/smm_test.c b/tools/testing/selftests/kvm/x86_64/smm_test.c
>> new file mode 100644
>> index 000000000000..3452b592588a
>> --- /dev/null
>> +++ b/tools/testing/selftests/kvm/x86_64/smm_test.c
>> @@ -0,0 +1,159 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (C) 2018, Red Hat, Inc.
>> + *
>> + * Tests for SMM.
>> + */
>> +#define _GNU_SOURCE /* for program_invocation_short_name */
>> +#include <fcntl.h>
>> +#include <stdio.h>
>> +#include <stdlib.h>
>> +#include <stdint.h>
>> +#include <string.h>
>> +#include <sys/ioctl.h>
>> +
>> +#include "test_util.h"
>> +
>> +#include "kvm_util.h"
>> +
>> +#include "vmx.h"
>> +
>> +#define VCPU_ID 1
>> +
>> +#define PAGE_SIZE 4096
>> +
>> +#define SMRAM_SIZE (16 * PAGE_SIZE)
>> +#define SMRAM_GPA 0x1000000
>> +#define SMRAM_STAGE 0xfe
>> +
>> +#define STR(x) #x
>> +#define XSTR(s) STR(s)
>> +
>> +#define SYNC_PORT 0xe
>> +#define DONE 0xff
>> +
>> +/*
>> + * This is compiled as normal 64-bit code, however, SMI handler is executed
>> + * in real-address mode. To stay simple we're limiting ourselves to a mode
>> + * independent subset of asm here.
>> + * SMI handler always report back fixed stage SMRAM_STAGE.
>> + */
>> +void smi_handler(void)
>> +{
>> + asm volatile("mov $" XSTR(SMRAM_STAGE) ", %al \n"
>> + "in $" XSTR(SYNC_PORT) ", %al \n"
>> + "rsm \n");
>> +}
>> +/* This should change if the code above changes in length */
>> +#define SMI_HANDLER_SIZE 6
>
> Here I had similar code but I just wrote hex instead. :)
>
I enjoyed playing the game "find the right instruction" so we don't need
to have a separate .s file. It seems we're good with the 3-instruction
stub.
>> +
>> +void sync_with_host(uint64_t phase)
>> +{
>> + asm volatile("in $" XSTR(SYNC_PORT)", %%al \n"
>> + : : "a" (phase));
>> +}
>> +
>> +void self_smi(void)
>> +{
>> + wrmsr(APIC_BASE_MSR + (APIC_ICR >> 4),
>> + APIC_DEST_SELF | APIC_INT_ASSERT | APIC_DM_SMI);
>> +}
>> +
>> +void guest_code(struct vmx_pages *vmx_pages)
>> +{
>> + uint64_t apicbase = rdmsr(MSR_IA32_APICBASE);
>> +
>> + sync_with_host(1);
>> +
>> + wrmsr(MSR_IA32_APICBASE, apicbase | X2APIC_ENABLE);
>> +
>> + sync_with_host(2);
>> +
>> + self_smi();
>> +
>> + sync_with_host(4);
>> +
>> + if (vmx_pages) {
>> + GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
>> +
>> + sync_with_host(5);
>> +
>> + self_smi();
>> +
>> + sync_with_host(7);
>> + }
>> +
>> + sync_with_host(DONE);
>> +}
>> +
>> +int main(int argc, char *argv[])
>> +{
>> + struct vmx_pages *vmx_pages = NULL;
>> + vm_vaddr_t vmx_pages_gva = 0;
>> +
>> + struct kvm_regs regs;
>> + struct kvm_vm *vm;
>> + struct kvm_run *run;
>> + struct kvm_x86_state *state;
>> + int stage, stage_reported;
>> +
>> + /* Create VM */
>> + vm = vm_create_default(VCPU_ID, 0, guest_code);
>> +
>> + vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
>> +
>> + run = vcpu_state(vm, VCPU_ID);
>> +
>> + vcpu_regs_get(vm, VCPU_ID, ®s);
>
> Unused?
>
Yes, probably a leftover from state_test
>> +
>> + vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, SMRAM_GPA,
>> + 1 << 16 | 1, SMRAM_SIZE/PAGE_SIZE, 0);
>
> Better add a vm_phy_pages_alloc here.
>
> I'll debug the remaining failure and post it again.
Thanks!
>
> Paolo
>
>> + memset(addr_gpa2hva(vm, SMRAM_GPA), 0x0, SMRAM_SIZE);
>> + memcpy(addr_gpa2hva(vm, SMRAM_GPA) + 0x8000, smi_handler,
>> + SMI_HANDLER_SIZE);
>> +
>> + vcpu_set_msr(vm, VCPU_ID, MSR_IA32_SMBASE, SMRAM_GPA);
>> +
>> + if (kvm_check_cap(KVM_CAP_NESTED_STATE)) {
>> + vmx_pages = vcpu_alloc_vmx(vm, &vmx_pages_gva);
>> + vcpu_args_set(vm, VCPU_ID, 1, vmx_pages_gva);
>> + } else {
>> + printf("will skip SMM test with VMX enabled\n");
>> + vcpu_args_set(vm, VCPU_ID, 1, 0);
>> + }
>> +
>> + for (stage = 1;; stage++) {
>> + _vcpu_run(vm, VCPU_ID);
>> + TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
>> + "Stage %d: unexpected exit reason: %u (%s),\n",
>> + stage, run->exit_reason,
>> + exit_reason_str(run->exit_reason));
>> +
>> + memset(®s, 0, sizeof(regs));
>> + vcpu_regs_get(vm, VCPU_ID, ®s);
>> +
>> + stage_reported = regs.rax & 0xff;
>> +
>> + if (stage_reported == DONE)
>> + goto done;
>> +
>> + TEST_ASSERT(stage_reported == stage ||
>> + stage_reported == SMRAM_STAGE,
>> + "Unexpected stage: #%x, got %x",
>> + stage, stage_reported);
>> +
>> + /* This piece of code needs sharing with state_test/evmcs_test */
>> + state = vcpu_save_state(vm, VCPU_ID);
>> + kvm_vm_release(vm);
>> + kvm_vm_restart(vm, O_RDWR);
>> + vm_vcpu_add(vm, VCPU_ID, 0, 0);
>> + vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
>> + vcpu_load_state(vm, VCPU_ID, state);
>> + run = vcpu_state(vm, VCPU_ID);
>> + free(state);
>> + }
>> +
>> +done:
>> + kvm_vm_free(vm);
>> +}
>>
>
--
Vitaly
^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2019-04-10 10:32 UTC | newest]
Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-03-26 13:07 [PATCH] KVM: x86: nVMX: allow RSM to restore VMXE CR4 flag Vitaly Kuznetsov
2019-03-26 13:11 ` Liran Alon
2019-03-26 13:48 ` Vitaly Kuznetsov
2019-03-26 15:02 ` Liran Alon
2019-03-27 10:08 ` Vitaly Kuznetsov
[not found] ` <20190327192946.19128-1-sean.j.christopherson@intel.com>
[not found] ` <87va03ml7n.fsf@vitty.brq.redhat.com>
[not found] ` <CALMp9eQPwFy5GvjDbE9wQQYEDdYfHzEwm6n1XZgQ_hCuk9vp+Q@mail.gmail.com>
2019-04-09 8:21 ` Vitaly Kuznetsov
2019-04-09 16:31 ` Paolo Bonzini
2019-04-10 9:38 ` [RFC] selftests: kvm: add a selftest for SMM Vitaly Kuznetsov
2019-04-10 10:10 ` Paolo Bonzini
2019-04-10 10:32 ` Vitaly Kuznetsov
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