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From: "Yang, Weijiang" <weijiang.yang@intel.com>
To: "Li, Xin3" <xin3.li@intel.com>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"pbonzini@redhat.com" <pbonzini@redhat.com>, "Christopherson,,
	Sean" <seanjc@google.com>, "Gao, Chao" <chao.gao@intel.com>,
	"hpa@zytor.com" <hpa@zytor.com>,
	"Li, Xiaoyao" <Xiaoyao.Li@intel.com>
Subject: Re: [PATCH 4/4] target/i386: add live migration support for FRED
Date: Thu, 21 Sep 2023 17:03:49 +0800	[thread overview]
Message-ID: <ce2bd892-0c42-3d7b-cd59-a397b840fee5@intel.com> (raw)
In-Reply-To: <20230901053022.18672-5-xin3.li@intel.com>

On 9/1/2023 1:30 PM, Li, Xin3 wrote:
> FRED CPU states are managed in 10 FRED MSRs, in addtion to a few existing
> CPU registers and MSRs, e.g., the CR4.FRED bit.
>
> Add the 10 new FRED MSRs to x86 CPUArchState for live migration support.
>
> Tested-by: Shan Kang <shan.kang@intel.com>
> Signed-off-by: Xin Li <xin3.li@intel.com>
> ---
>   target/i386/cpu.h     | 24 +++++++++++++++++++
>   target/i386/kvm/kvm.c | 54 +++++++++++++++++++++++++++++++++++++++++++
>   target/i386/machine.c | 10 ++++++++
>   3 files changed, 88 insertions(+)
>
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index 924819a64c..a36a1a58c4 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -529,6 +529,20 @@ typedef enum X86Seg {
>   #define MSR_IA32_XFD                    0x000001c4
>   #define MSR_IA32_XFD_ERR                0x000001c5
>   
> +#define MSR_IA32_PL0_SSP                0x000006a4       /* Stack level 0 shadow stack pointer in ring 0 */
> +
> +/* FRED MSRs */
> +#define MSR_IA32_FRED_RSP0              0x000001cc       /* Stack level 0 regular stack pointer */
> +#define MSR_IA32_FRED_RSP1              0x000001cd       /* Stack level 1 regular stack pointer */
> +#define MSR_IA32_FRED_RSP2              0x000001ce       /* Stack level 2 regular stack pointer */
> +#define MSR_IA32_FRED_RSP3              0x000001cf       /* Stack level 3 regular stack pointer */
> +#define MSR_IA32_FRED_STKLVLS           0x000001d0       /* FRED exception stack levels */
> +#define MSR_IA32_FRED_SSP0              MSR_IA32_PL0_SSP /* Stack level 0 shadow stack pointer in ring 0 */
> +#define MSR_IA32_FRED_SSP1              0x000001d1       /* Stack level 1 shadow stack pointer in ring 0 */
> +#define MSR_IA32_FRED_SSP2              0x000001d2       /* Stack level 2 shadow stack pointer in ring 0 */
> +#define MSR_IA32_FRED_SSP3              0x000001d3       /* Stack level 3 shadow stack pointer in ring 0 */
> +#define MSR_IA32_FRED_CONFIG            0x000001d4       /* FRED Entrypoint and interrupt stack level */
> +
>   #define MSR_IA32_BNDCFGS                0x00000d90
>   #define MSR_IA32_XSS                    0x00000da0
>   #define MSR_IA32_UMWAIT_CONTROL         0xe1
> @@ -1680,6 +1694,16 @@ typedef struct CPUArchState {
>       target_ulong cstar;
>       target_ulong fmask;
>       target_ulong kernelgsbase;
> +    target_ulong fred_rsp0;
> +    target_ulong fred_rsp1;
> +    target_ulong fred_rsp2;
> +    target_ulong fred_rsp3;
> +    target_ulong fred_stklvls;
> +    target_ulong fred_ssp0;
> +    target_ulong fred_ssp1;
> +    target_ulong fred_ssp2;
> +    target_ulong fred_ssp3;
> +    target_ulong fred_config;
>   #endif
>   
>       uint64_t tsc_adjust;
> diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
> index 639a242ad8..4b241c82d8 100644
> --- a/target/i386/kvm/kvm.c
> +++ b/target/i386/kvm/kvm.c
> @@ -3401,6 +3401,18 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
>           kvm_msr_entry_add(cpu, MSR_KERNELGSBASE, env->kernelgsbase);
>           kvm_msr_entry_add(cpu, MSR_FMASK, env->fmask);
>           kvm_msr_entry_add(cpu, MSR_LSTAR, env->lstar);
> +        if (env->features[FEAT_7_1_EAX] & CPUID_7_1_EAX_FRED) {
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_RSP0, env->fred_rsp0);
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_RSP1, env->fred_rsp1);
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_RSP2, env->fred_rsp2);
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_RSP3, env->fred_rsp3);
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_STKLVLS, env->fred_stklvls);
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_SSP0, env->fred_ssp0);
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_SSP1, env->fred_ssp1);
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_SSP2, env->fred_ssp2);
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_SSP3, env->fred_ssp3);
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_CONFIG, env->fred_config);
> +        }
>       }
>   #endif
>   
> @@ -3901,6 +3913,18 @@ static int kvm_get_msrs(X86CPU *cpu)
>           kvm_msr_entry_add(cpu, MSR_KERNELGSBASE, 0);
>           kvm_msr_entry_add(cpu, MSR_FMASK, 0);
>           kvm_msr_entry_add(cpu, MSR_LSTAR, 0);
> +        if (env->features[FEAT_7_1_EAX] & CPUID_7_1_EAX_FRED) {
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_RSP0, 0);
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_RSP1, 0);
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_RSP2, 0);
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_RSP3, 0);
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_STKLVLS, 0);
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_SSP0, 0);
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_SSP1, 0);
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_SSP2, 0);
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_SSP3, 0);
> +            kvm_msr_entry_add(cpu, MSR_IA32_FRED_CONFIG, 0);
> +        }
>       }
>   #endif
>       kvm_msr_entry_add(cpu, MSR_KVM_SYSTEM_TIME, 0);
> @@ -4123,6 +4147,36 @@ static int kvm_get_msrs(X86CPU *cpu)
>           case MSR_LSTAR:
>               env->lstar = msrs[i].data;
>               break;
> +        case MSR_IA32_FRED_RSP0:
> +            env->fred_rsp0 = msrs[i].data;
> +            break;
> +        case MSR_IA32_FRED_RSP1:
> +            env->fred_rsp1 = msrs[i].data;
> +            break;
> +        case MSR_IA32_FRED_RSP2:
> +            env->fred_rsp2 = msrs[i].data;
> +            break;
> +        case MSR_IA32_FRED_RSP3:
> +            env->fred_rsp3 = msrs[i].data;
> +            break;
> +        case MSR_IA32_FRED_STKLVLS:
> +            env->fred_stklvls = msrs[i].data;
> +            break;
> +        case MSR_IA32_FRED_SSP0:
> +            env->fred_ssp0 = msrs[i].data;
> +            break;
> +        case MSR_IA32_FRED_SSP1:
> +            env->fred_ssp1 = msrs[i].data;
> +            break;
> +        case MSR_IA32_FRED_SSP2:
> +            env->fred_ssp2 = msrs[i].data;
> +            break;
> +        case MSR_IA32_FRED_SSP3:
> +            env->fred_ssp3 = msrs[i].data;
> +            break;
> +        case MSR_IA32_FRED_CONFIG:
> +            env->fred_config = msrs[i].data;
> +            break;
>   #endif
>           case MSR_IA32_TSC:
>               env->tsc = msrs[i].data;
> diff --git a/target/i386/machine.c b/target/i386/machine.c
> index c7ac8084b2..5c722a49c5 100644
> --- a/target/i386/machine.c
> +++ b/target/i386/machine.c
> @@ -1652,6 +1652,16 @@ const VMStateDescription vmstate_x86_cpu = {
>           VMSTATE_UINT64(env.cstar, X86CPU),
>           VMSTATE_UINT64(env.fmask, X86CPU),
>           VMSTATE_UINT64(env.kernelgsbase, X86CPU),
> +        VMSTATE_UINT64(env.fred_rsp0, X86CPU),
> +        VMSTATE_UINT64(env.fred_rsp1, X86CPU),
> +        VMSTATE_UINT64(env.fred_rsp2, X86CPU),
> +        VMSTATE_UINT64(env.fred_rsp3, X86CPU),
> +        VMSTATE_UINT64(env.fred_stklvls, X86CPU),
> +        VMSTATE_UINT64(env.fred_ssp0, X86CPU),
> +        VMSTATE_UINT64(env.fred_ssp1, X86CPU),
> +        VMSTATE_UINT64(env.fred_ssp2, X86CPU),
> +        VMSTATE_UINT64(env.fred_ssp3, X86CPU),
> +        VMSTATE_UINT64(env.fred_config, X86CPU),
>   #endif
>           VMSTATE_UINT32(env.smbase, X86CPU),
>   

IMO, it's better to split this patch into two, one is for FRED MSR access, the other is
for LM support.

And move the FRED MSRs from basic x86_cpu part to .subsections part because FRED
doesn't belong to basic CPU registers.  In the .subsections part, you may define a struct
to hold FRED MSRs then add  .needed callback helper for QEMU to query whether FRED
MSRs are necessary for live migration.

See other features, e.g., vmstate_msr_intel_sgx



  reply	other threads:[~2023-09-21  9:04 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-01  5:30 [PATCH 0/4] target/i386: add support for FRED Xin Li
2023-09-01  5:30 ` [PATCH 1/4] target/i386: add support for FRED in CPUID enumeration Xin Li
2023-09-01  5:30 ` [PATCH 2/4] target/i386: mark CR4.FRED not reserved Xin Li
2023-09-01  5:30 ` [PATCH 3/4] target/i386: enumerate VMX nested-exception support Xin Li
2023-09-26 15:37   ` Paolo Bonzini
2023-09-01  5:30 ` [PATCH 4/4] target/i386: add live migration support for FRED Xin Li
2023-09-21  9:03   ` Yang, Weijiang [this message]
2023-09-26  6:41     ` Li, Xin3

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