Re: [RFCv2 02/13] x86/kvm: Introduce KVM memory protection feature

2021-04-19 Thread Kirill A. Shutemov
On Fri, Apr 16, 2021 at 06:10:30PM +0200, Borislav Petkov wrote:
> On Fri, Apr 16, 2021 at 06:40:55PM +0300, Kirill A. Shutemov wrote:
> > Provide basic helpers, KVM_FEATURE, CPUID flag and a hypercall.
> > 
> > Host side doesn't provide the feature yet, so it is a dead code for now.
> > 
> > Signed-off-by: Kirill A. Shutemov 
> > ---
> >  arch/x86/include/asm/cpufeatures.h   |  1 +
> >  arch/x86/include/asm/kvm_para.h  |  5 +
> >  arch/x86/include/uapi/asm/kvm_para.h |  3 ++-
> >  arch/x86/kernel/kvm.c| 17 +
> >  include/uapi/linux/kvm_para.h|  3 ++-
> >  5 files changed, 27 insertions(+), 2 deletions(-)
> > 
> > diff --git a/arch/x86/include/asm/cpufeatures.h 
> > b/arch/x86/include/asm/cpufeatures.h
> > index 84b887825f12..d8f3d2619913 100644
> > --- a/arch/x86/include/asm/cpufeatures.h
> > +++ b/arch/x86/include/asm/cpufeatures.h
> > @@ -238,6 +238,7 @@
> >  #define X86_FEATURE_VMW_VMMCALL( 8*32+19) /* "" VMware prefers 
> > VMMCALL hypercall instruction */
> >  #define X86_FEATURE_SEV_ES ( 8*32+20) /* AMD Secure Encrypted 
> > Virtualization - Encrypted State */
> >  #define X86_FEATURE_VM_PAGE_FLUSH  ( 8*32+21) /* "" VM Page Flush MSR is 
> > supported */
> > +#define X86_FEATURE_KVM_MEM_PROTECTED  ( 8*32+22) /* "" KVM memory 
> > protection extension */
> 
> That feature bit is still unused.

Sorry. Will drop it.

-- 
 Kirill A. Shutemov


Re: [RFCv2 02/13] x86/kvm: Introduce KVM memory protection feature

2021-04-16 Thread Borislav Petkov
On Fri, Apr 16, 2021 at 06:40:55PM +0300, Kirill A. Shutemov wrote:
> Provide basic helpers, KVM_FEATURE, CPUID flag and a hypercall.
> 
> Host side doesn't provide the feature yet, so it is a dead code for now.
> 
> Signed-off-by: Kirill A. Shutemov 
> ---
>  arch/x86/include/asm/cpufeatures.h   |  1 +
>  arch/x86/include/asm/kvm_para.h  |  5 +
>  arch/x86/include/uapi/asm/kvm_para.h |  3 ++-
>  arch/x86/kernel/kvm.c| 17 +
>  include/uapi/linux/kvm_para.h|  3 ++-
>  5 files changed, 27 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/include/asm/cpufeatures.h 
> b/arch/x86/include/asm/cpufeatures.h
> index 84b887825f12..d8f3d2619913 100644
> --- a/arch/x86/include/asm/cpufeatures.h
> +++ b/arch/x86/include/asm/cpufeatures.h
> @@ -238,6 +238,7 @@
>  #define X86_FEATURE_VMW_VMMCALL  ( 8*32+19) /* "" VMware prefers 
> VMMCALL hypercall instruction */
>  #define X86_FEATURE_SEV_ES   ( 8*32+20) /* AMD Secure Encrypted 
> Virtualization - Encrypted State */
>  #define X86_FEATURE_VM_PAGE_FLUSH( 8*32+21) /* "" VM Page Flush MSR is 
> supported */
> +#define X86_FEATURE_KVM_MEM_PROTECTED( 8*32+22) /* "" KVM memory 
> protection extension */

That feature bit is still unused.

-- 
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette


[RFCv2 02/13] x86/kvm: Introduce KVM memory protection feature

2021-04-16 Thread Kirill A. Shutemov
Provide basic helpers, KVM_FEATURE, CPUID flag and a hypercall.

Host side doesn't provide the feature yet, so it is a dead code for now.

Signed-off-by: Kirill A. Shutemov 
---
 arch/x86/include/asm/cpufeatures.h   |  1 +
 arch/x86/include/asm/kvm_para.h  |  5 +
 arch/x86/include/uapi/asm/kvm_para.h |  3 ++-
 arch/x86/kernel/kvm.c| 17 +
 include/uapi/linux/kvm_para.h|  3 ++-
 5 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/cpufeatures.h 
b/arch/x86/include/asm/cpufeatures.h
index 84b887825f12..d8f3d2619913 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -238,6 +238,7 @@
 #define X86_FEATURE_VMW_VMMCALL( 8*32+19) /* "" VMware prefers 
VMMCALL hypercall instruction */
 #define X86_FEATURE_SEV_ES ( 8*32+20) /* AMD Secure Encrypted 
Virtualization - Encrypted State */
 #define X86_FEATURE_VM_PAGE_FLUSH  ( 8*32+21) /* "" VM Page Flush MSR is 
supported */
+#define X86_FEATURE_KVM_MEM_PROTECTED  ( 8*32+22) /* "" KVM memory protection 
extension */
 
 /* Intel-defined CPU features, CPUID level 0x0007:0 (EBX), word 9 */
 #define X86_FEATURE_FSGSBASE   ( 9*32+ 0) /* RDFSBASE, WRFSBASE, 
RDGSBASE, WRGSBASE instructions*/
diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
index 338119852512..74aea18f3130 100644
--- a/arch/x86/include/asm/kvm_para.h
+++ b/arch/x86/include/asm/kvm_para.h
@@ -11,11 +11,16 @@ extern void kvmclock_init(void);
 
 #ifdef CONFIG_KVM_GUEST
 bool kvm_check_and_clear_guest_paused(void);
+bool kvm_mem_protected(void);
 #else
 static inline bool kvm_check_and_clear_guest_paused(void)
 {
return false;
 }
+static inline bool kvm_mem_protected(void)
+{
+   return false;
+}
 #endif /* CONFIG_KVM_GUEST */
 
 #define KVM_HYPERCALL \
diff --git a/arch/x86/include/uapi/asm/kvm_para.h 
b/arch/x86/include/uapi/asm/kvm_para.h
index 950afebfba88..8d32c41861c9 100644
--- a/arch/x86/include/uapi/asm/kvm_para.h
+++ b/arch/x86/include/uapi/asm/kvm_para.h
@@ -28,11 +28,12 @@
 #define KVM_FEATURE_PV_UNHALT  7
 #define KVM_FEATURE_PV_TLB_FLUSH   9
 #define KVM_FEATURE_ASYNC_PF_VMEXIT10
-#define KVM_FEATURE_PV_SEND_IPI11
+#define KVM_FEATURE_PV_SEND_IPI11
 #define KVM_FEATURE_POLL_CONTROL   12
 #define KVM_FEATURE_PV_SCHED_YIELD 13
 #define KVM_FEATURE_ASYNC_PF_INT   14
 #define KVM_FEATURE_MSI_EXT_DEST_ID15
+#define KVM_FEATURE_MEM_PROTECTED  16
 
 #define KVM_HINTS_REALTIME  0
 
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 5e78e01ca3b4..aed6034fcac1 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -39,6 +39,13 @@
 #include 
 #include 
 
+static bool mem_protected;
+
+bool kvm_mem_protected(void)
+{
+   return mem_protected;
+}
+
 DEFINE_STATIC_KEY_FALSE(kvm_async_pf_enabled);
 
 static int kvmapf = 1;
@@ -749,6 +756,16 @@ static void __init kvm_init_platform(void)
 {
kvmclock_init();
x86_platform.apic_post_init = kvm_apic_init;
+
+   if (kvm_para_has_feature(KVM_FEATURE_MEM_PROTECTED)) {
+   if (kvm_hypercall0(KVM_HC_ENABLE_MEM_PROTECTED)) {
+   panic("Failed to enable KVM memory protection");
+   }
+
+   pr_info("KVM memory protection enabled\n");
+   mem_protected = true;
+   setup_force_cpu_cap(X86_FEATURE_KVM_MEM_PROTECTED);
+   }
 }
 
 #if defined(CONFIG_AMD_MEM_ENCRYPT)
diff --git a/include/uapi/linux/kvm_para.h b/include/uapi/linux/kvm_para.h
index 8b86609849b9..1a216f32e572 100644
--- a/include/uapi/linux/kvm_para.h
+++ b/include/uapi/linux/kvm_para.h
@@ -27,8 +27,9 @@
 #define KVM_HC_MIPS_EXIT_VM7
 #define KVM_HC_MIPS_CONSOLE_OUTPUT 8
 #define KVM_HC_CLOCK_PAIRING   9
-#define KVM_HC_SEND_IPI10
+#define KVM_HC_SEND_IPI10
 #define KVM_HC_SCHED_YIELD 11
+#define KVM_HC_ENABLE_MEM_PROTECTED12
 
 /*
  * hypercalls use architecture specific
-- 
2.26.3