search for: vmcall

From: Mihai Don?u <mdontu at bitdefender.com> It can happened to end up emulating the VMCALL instruction as a result of the handling of an EPT write fault. In this situation, the emulator will try to unconditionally patch the correct hypercall opcode bytes using emulator_write_emulated(). However, this last call uses the fault GPA (if available) or walks the guest page tables at RIP, other...

From: Mihai Don?u <mdontu at bitdefender.com> It can happened to end up emulating the VMCALL instruction as a result of the handling of an EPT write fault. In this situation, the emulator will try to unconditionally patch the correct hypercall opcode bytes using emulator_write_emulated(). However, this last call uses the fault GPA (if available) or walks the guest page tables at RIP, other...

...efficient: - We have a huge space for CPUID leaves - CPUID also works for user-level - It can take an additional 32-bit parameter (ECX), and returns 4 32-bit values (EAX, EBX, ECX, and EDX). RDMSR, for example, returns a 64-bit value. Basically we can use it to implement a hypercall (rather than VMCALL). For example, - CPUID 0x48000001.EAX would return the feature presence (e.g. in EBX), and the result in EDX:EAX (if present) at the same time, or - CPUID 0x48000001.EAX would return the feature presence only, and CPUID 0x48000002.EAX (acts like a hypercall) returns up to 4 32-bit values. -- Jun...

...efficient: - We have a huge space for CPUID leaves - CPUID also works for user-level - It can take an additional 32-bit parameter (ECX), and returns 4 32-bit values (EAX, EBX, ECX, and EDX). RDMSR, for example, returns a 64-bit value. Basically we can use it to implement a hypercall (rather than VMCALL). For example, - CPUID 0x48000001.EAX would return the feature presence (e.g. in EBX), and the result in EDX:EAX (if present) at the same time, or - CPUID 0x48000001.EAX would return the feature presence only, and CPUID 0x48000002.EAX (acts like a hypercall) returns up to 4 32-bit values. -- Jun...

...calls from HVM domain (e.g. HYPERVISOR_add_to_physmap). However, it does not work when I am trying to invoke it from HVM Linux guest. Basically, I don''t see that anything happens on hypervisor''s side. I also grep''ed the guest code for ''vmmcall''/''vmcall'' and did not find anything. Is it possible to do it at all? Is it possible to make hypercalls from HVM domains or are they simply used for tools responsible to load HVM domain? Also, are they allowed (if allowed at all) from stubdom, ioemu, or both configurations? I am using latest Xen ve...

I am learning xen's memory management recently. I find most docs is how to use the hypercall related memory management. Can somesome tell me where is the implementation of the them in the xen source. Or some docs explaining it will be ideal. 年少不惧江湖老，放歌四海任逍遥。未解前路多少事，欲与青天试比高。 _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org

...++ b/arch/x86/include/asm/cpufeature.h > @@ -216,6 +216,7 @@ > #define X86_FEATURE_PAUSEFILTER ( 8*32+13) /* AMD filtered pause intercept */ > #define X86_FEATURE_PFTHRESHOLD ( 8*32+14) /* AMD pause filter threshold */ > #define X86_FEATURE_VMMCALL ( 8*32+15) /* Prefer vmmcall to vmcall */ > +#define X86_FEATURE_XENPV ( 8*32+16) /* Xen paravirtual guest */ > This bit is highly magical and I think we need Borislav's ack. --Andy

...++ b/arch/x86/include/asm/cpufeature.h > @@ -216,6 +216,7 @@ > #define X86_FEATURE_PAUSEFILTER ( 8*32+13) /* AMD filtered pause intercept */ > #define X86_FEATURE_PFTHRESHOLD ( 8*32+14) /* AMD pause filter threshold */ > #define X86_FEATURE_VMMCALL ( 8*32+15) /* Prefer vmmcall to vmcall */ > +#define X86_FEATURE_XENPV ( 8*32+16) /* Xen paravirtual guest */ > This bit is highly magical and I think we need Borislav's ack. --Andy

Hi all, I've been working on a set of easy-to-run benchmarks for hypervisor optimization called virtbench, and the latest commit adds Xen support. http://ozlabs.org/~rusty/virtbench http://ozlabs.org/~rusty/virtbench/?archive/tip.tar.bz2 >From the README: # Build the code make # Set the guest kernel location and maybe more vi ./SETTINGS # Run the benchmark (local mode)

Hi all, I've been working on a set of easy-to-run benchmarks for hypervisor optimization called virtbench, and the latest commit adds Xen support. http://ozlabs.org/~rusty/virtbench http://ozlabs.org/~rusty/virtbench/?archive/tip.tar.bz2 >From the README: # Build the code make # Set the guest kernel location and maybe more vi ./SETTINGS # Run the benchmark (local mode)

Hi all, I've been working on a set of easy-to-run benchmarks for hypervisor optimization called virtbench, and the latest commit adds Xen support. http://ozlabs.org/~rusty/virtbench http://ozlabs.org/~rusty/virtbench/?archive/tip.tar.bz2 >From the README: # Build the code make # Set the guest kernel location and maybe more vi ./SETTINGS # Run the benchmark (local mode)

...of different VM exit types of transactions and their emulation on KVM on x86 (it would be trivial to use memory BARs on non x86 platforms if they don't have PIO). Example benchmark (cycles per transaction): (io access) outw 1737 (memory access) movw 4341 for comparison: (hypercall access): vmcall 1566 (pv memory access) movw_fast 1817 (*explanation what this is below) This creates a problem if we want to make virtio devices proper PCI express devices with native hotplug support. This is because each hotpluggable PCI express device always has a PCI express port (port per device), where eac...

...of different VM exit types of transactions and their emulation on KVM on x86 (it would be trivial to use memory BARs on non x86 platforms if they don't have PIO). Example benchmark (cycles per transaction): (io access) outw 1737 (memory access) movw 4341 for comparison: (hypercall access): vmcall 1566 (pv memory access) movw_fast 1817 (*explanation what this is below) This creates a problem if we want to make virtio devices proper PCI express devices with native hotplug support. This is because each hotpluggable PCI express device always has a PCI express port (port per device), where eac...

...pace for CPUID leaves > - CPUID also works for user-level > - It can take an additional 32-bit parameter (ECX), and returns 4 > 32-bit values (EAX, EBX, ECX, and EDX). RDMSR, for example, returns a > 64-bit value. > > Basically we can use it to implement a hypercall (rather than VMCALL). > > For example, > - CPUID 0x48000001.EAX would return the feature presence (e.g. in > EBX), and the result in EDX:EAX (if present) at the same time, or > - CPUID 0x48000001.EAX would return the feature presence only, and > CPUID 0x48000002.EAX (acts like a hypercall) returns u...

...t; - CPUID also works for user-level > > - It can take an additional 32-bit parameter (ECX), and returns 4 > > 32-bit values (EAX, EBX, ECX, and EDX). RDMSR, for example, returns a > > 64-bit value. > > > > Basically we can use it to implement a hypercall (rather than VMCALL). > > > > For example, > > - CPUID 0x48000001.EAX would return the feature presence (e.g. in > > EBX), and the result in EDX:EAX (if present) at the same time, or > > - CPUID 0x48000001.EAX would return the feature presence only, and > > CPUID 0x48000002.EAX (act...

...t; - CPUID also works for user-level > > - It can take an additional 32-bit parameter (ECX), and returns 4 > > 32-bit values (EAX, EBX, ECX, and EDX). RDMSR, for example, returns a > > 64-bit value. > > > > Basically we can use it to implement a hypercall (rather than VMCALL). > > > > For example, > > - CPUID 0x48000001.EAX would return the feature presence (e.g. in > > EBX), and the result in EDX:EAX (if present) at the same time, or > > - CPUID 0x48000001.EAX would return the feature presence only, and > > CPUID 0x48000002.EAX (act...

...features.h b/arch/x86/include/asm/cpufeatures.h index db189945e9b0..ade59fca283a 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -234,6 +234,7 @@ #define X86_FEATURE_EPT_AD ( 8*32+17) /* Intel Extended Page Table access-dirty bit */ #define X86_FEATURE_VMCALL ( 8*32+18) /* "" Hypervisor supports the VMCALL instruction */ #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 */ /* Intel-defi...

From: Mihai Don?u <mdontu at bitdefender.com> It can happened for us to end up emulating the VMCALL instruction as a result of the handling of an EPT write fault. In this situation, the emulator will try to unconditionally patch the correct hypercall opcode bytes using emulator_write_emulated(). However, this last call uses the fault GPA (if available) or walks the guest page tables at RIP, other...

..."; we revert to using (just as questionable but more reliable) int $15 for hypercalls. I didn't revert the register mapping, so we still use the same calling convention as kvm. KVM in more recent incarnations stopped injecting a fault when a guest tried to use the VMCALL instruction from ring 1, so lguest under kvm fails to make hypercalls. It was nice to share code with our KVM cousins, but this was overreach. Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> Cc: Matias Zabaljauregui <zabaljauregui at gmail.com> Cc: Avi...

..."; we revert to using (just as questionable but more reliable) int $15 for hypercalls. I didn't revert the register mapping, so we still use the same calling convention as kvm. KVM in more recent incarnations stopped injecting a fault when a guest tried to use the VMCALL instruction from ring 1, so lguest under kvm fails to make hypercalls. It was nice to share code with our KVM cousins, but this was overreach. Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> Cc: Matias Zabaljauregui <zabaljauregui at gmail.com> Cc: Avi...