lkml.org 
[lkml]   [2020]   [Feb]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 53/62] x86/paravirt: Allow hypervisor specific VMMCALL handling under SEV-ES
    Date
    From: Joerg Roedel <jroedel@suse.de>

    Add two new paravirt callbacks to provide hypervisor specific processor
    state in the GHCB and to copy state from the hypervisor back to the
    processor.

    Signed-off-by: Joerg Roedel <jroedel@suse.de>
    ---
    arch/x86/include/asm/x86_init.h | 16 +++++++++++++++-
    arch/x86/kernel/sev-es.c | 12 ++++++++++++
    2 files changed, 27 insertions(+), 1 deletion(-)

    diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
    index 96d9cd208610..c4790ec279cc 100644
    --- a/arch/x86/include/asm/x86_init.h
    +++ b/arch/x86/include/asm/x86_init.h
    @@ -4,8 +4,10 @@

    #include <asm/bootparam.h>

    +struct ghcb;
    struct mpc_bus;
    struct mpc_cpu;
    +struct pt_regs;
    struct mpc_table;
    struct cpuinfo_x86;

    @@ -238,10 +240,22 @@ struct x86_legacy_features {
    /**
    * struct x86_hyper_runtime - x86 hypervisor specific runtime callbacks
    *
    - * @pin_vcpu: pin current vcpu to specified physical cpu (run rarely)
    + * @pin_vcpu: pin current vcpu to specified physical
    + * cpu (run rarely)
    + * @sev_es_hcall_prepare: Load additional hypervisor-specific
    + * state into the GHCB when doing a VMMCALL under
    + * SEV-ES. Called from the #VC exception handler.
    + * @sev_es_hcall_finish: Copies state from the GHCB back into the
    + * processor (or pt_regs). Also runs checks on the
    + * state returned from the hypervisor after a
    + * VMMCALL under SEV-ES. Needs to return 'false'
    + * if the checks fail. Called from the #VC
    + * exception handler.
    */
    struct x86_hyper_runtime {
    void (*pin_vcpu)(int cpu);
    + void (*sev_es_hcall_prepare)(struct ghcb *ghcb, struct pt_regs *regs);
    + bool (*sev_es_hcall_finish)(struct ghcb *ghcb, struct pt_regs *regs);
    };

    /**
    diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c
    index 700f75fc13e7..6924bb1ad8b2 100644
    --- a/arch/x86/kernel/sev-es.c
    +++ b/arch/x86/kernel/sev-es.c
    @@ -349,6 +349,9 @@ static enum es_result handle_vmmcall(struct ghcb *ghcb,
    ghcb_set_rax(ghcb, ctxt->regs->ax);
    ghcb_set_cpl(ghcb, user_mode(ctxt->regs) ? 3 : 0);

    + if (x86_platform.hyper.sev_es_hcall_prepare)
    + x86_platform.hyper.sev_es_hcall_prepare(ghcb, ctxt->regs);
    +
    ret = ghcb_hv_call(ghcb, ctxt, SVM_EXIT_VMMCALL, 0, 0);
    if (ret != ES_OK)
    return ret;
    @@ -358,6 +361,15 @@ static enum es_result handle_vmmcall(struct ghcb *ghcb,

    ctxt->regs->ax = ghcb->save.rax;

    + /*
    + * Call sev_es_hcall_finish() after regs->ax is already set.
    + * This allows the hypervisor handler to overwrite it again if
    + * necessary.
    + */
    + if (x86_platform.hyper.sev_es_hcall_finish &&
    + !x86_platform.hyper.sev_es_hcall_finish(ghcb, ctxt->regs))
    + return ES_VMM_ERROR;
    +
    return ES_OK;
    }

    --
    2.17.1
    \
     
     \ /
      Last update: 2020-02-11 14:55    [W:2.870 / U:0.480 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site