Commit 483c6ad4 authored by Borislav Petkov's avatar Borislav Petkov Committed by Eduardo Habkost
Browse files

target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models CPU models 



The missing functionality was added ~3 years ago with the Linux commit

  46896c73c1a4 ("KVM: svm: add support for RDTSCP")

so reenable RDTSCP support on those CPU models.

Opteron_G2 - being family 15, model 6, doesn't have RDTSCP support
(the real hardware doesn't have it. K8 got RDTSCP support with the NPT
models, i.e., models >= 0x40).

Document the host's minimum required kernel version, while at it.

Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Message-ID: <20181212200803.GG6653@zn.tnic>
[ehabkost: moved compat properties code to pc.c]
Signed-off-by: default avatarEduardo Habkost <ehabkost@redhat.com>
parent a2b107db

hw/i386/pc.c

+3 −0
Original line number Diff line number Diff line
@@ -112,6 +112,9 @@ struct hpet_fw_config hpet_cfg = {.count = UINT8_MAX}; 


GlobalProperty pc_compat_3_1[] = {

    { "intel-iommu", "dma-drain", "off" },

    { "Opteron_G3" "-" TYPE_X86_CPU, "rdtscp", "off" },

    { "Opteron_G4" "-" TYPE_X86_CPU, "rdtscp", "off" },

    { "Opteron_G5" "-" TYPE_X86_CPU, "rdtscp", "off" },

};

const size_t pc_compat_3_1_len = G_N_ELEMENTS(pc_compat_3_1);

qemu-doc.texi

+13 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ 
* QEMU System emulator for non PC targets::

* QEMU Guest Agent::

* QEMU User space emulator::

* System requirements::

* Implementation notes::

* Deprecated features::

* Supported build platforms::
@@ -2813,6 +2814,18 @@ Act as if the host page size was 'pagesize' bytes 
Run the emulation in single step mode.

@end table



@node System requirements

@chapter System requirements



@section KVM kernel module



On x86_64 hosts, the default set of CPU features enabled by the KVM accelerator

require the host to be running Linux v4.5 or newer.



The OpteronG[345] CPU models require KVM support for RDTSCP, which was

added with Linux 4.5 which is supported by the major distros. And even

if RHEL7 has kernel 3.10, KVM there has the required functionality there

to make it close to a 4.5 or newer kernel.



@include qemu-tech.texi

target/i386/cpu.c

+4 −7
Original line number Diff line number Diff line
@@ -2736,7 +2736,6 @@ static X86CPUDefinition builtin_x86_defs[] = { 
            CPUID_DE | CPUID_FP87,

        .features[FEAT_1_ECX] =

            CPUID_EXT_CX16 | CPUID_EXT_SSE3,

        /* Missing: CPUID_EXT2_RDTSCP */

        .features[FEAT_8000_0001_EDX] =

            CPUID_EXT2_LM | CPUID_EXT2_NX | CPUID_EXT2_SYSCALL,

        .features[FEAT_8000_0001_ECX] =
@@ -2760,9 +2759,9 @@ static X86CPUDefinition builtin_x86_defs[] = { 
        .features[FEAT_1_ECX] =

            CPUID_EXT_POPCNT | CPUID_EXT_CX16 | CPUID_EXT_MONITOR |

            CPUID_EXT_SSE3,

        /* Missing: CPUID_EXT2_RDTSCP */

        .features[FEAT_8000_0001_EDX] =

            CPUID_EXT2_LM | CPUID_EXT2_NX | CPUID_EXT2_SYSCALL,

            CPUID_EXT2_LM | CPUID_EXT2_NX | CPUID_EXT2_SYSCALL |

            CPUID_EXT2_RDTSCP,

        .features[FEAT_8000_0001_ECX] =

            CPUID_EXT3_MISALIGNSSE | CPUID_EXT3_SSE4A |

            CPUID_EXT3_ABM | CPUID_EXT3_SVM | CPUID_EXT3_LAHF_LM,
@@ -2787,10 +2786,9 @@ static X86CPUDefinition builtin_x86_defs[] = { 
            CPUID_EXT_POPCNT | CPUID_EXT_SSE42 | CPUID_EXT_SSE41 |

            CPUID_EXT_CX16 | CPUID_EXT_SSSE3 | CPUID_EXT_PCLMULQDQ |

            CPUID_EXT_SSE3,

        /* Missing: CPUID_EXT2_RDTSCP */

        .features[FEAT_8000_0001_EDX] =

            CPUID_EXT2_LM | CPUID_EXT2_PDPE1GB | CPUID_EXT2_NX |

            CPUID_EXT2_SYSCALL,

            CPUID_EXT2_SYSCALL | CPUID_EXT2_RDTSCP,

        .features[FEAT_8000_0001_ECX] =

            CPUID_EXT3_FMA4 | CPUID_EXT3_XOP |

            CPUID_EXT3_3DNOWPREFETCH | CPUID_EXT3_MISALIGNSSE |
@@ -2818,10 +2816,9 @@ static X86CPUDefinition builtin_x86_defs[] = { 
            CPUID_EXT_AES | CPUID_EXT_POPCNT | CPUID_EXT_SSE42 |

            CPUID_EXT_SSE41 | CPUID_EXT_CX16 | CPUID_EXT_FMA |

            CPUID_EXT_SSSE3 | CPUID_EXT_PCLMULQDQ | CPUID_EXT_SSE3,

        /* Missing: CPUID_EXT2_RDTSCP */

        .features[FEAT_8000_0001_EDX] =

            CPUID_EXT2_LM | CPUID_EXT2_PDPE1GB | CPUID_EXT2_NX |

            CPUID_EXT2_SYSCALL,

            CPUID_EXT2_SYSCALL | CPUID_EXT2_RDTSCP,

        .features[FEAT_8000_0001_ECX] =

            CPUID_EXT3_TBM | CPUID_EXT3_FMA4 | CPUID_EXT3_XOP |

            CPUID_EXT3_3DNOWPREFETCH | CPUID_EXT3_MISALIGNSSE |