Re: [PATCH v2 2/3] KVM: x86: dump_vmcs should not conflate EFER and PAT presence in VMCS
From: David Edmondson
Date: Wed Feb 24 2021 - 09:51:58 EST
On Tuesday, 2021年02月23日 at 14:58:29 -08, Sean Christopherson wrote:
>
On Fri, Feb 19, 2021, David Edmondson wrote:
>
> Show EFER and PAT based on their individual entry/exit controls.
>
>
>
> Signed-off-by: David Edmondson <david.edmondson@xxxxxxxxxx>
>
> ---
>
> arch/x86/kvm/vmx/vmx.c | 19 ++++++++++---------
>
> 1 file changed, 10 insertions(+), 9 deletions(-)
>
>
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
>
> index 818051c9fa10..25090e3683ca 100644
>
> --- a/arch/x86/kvm/vmx/vmx.c
>
> +++ b/arch/x86/kvm/vmx/vmx.c
>
> @@ -5805,11 +5805,12 @@ void dump_vmcs(void)
>
> vmx_dump_sel("LDTR:", GUEST_LDTR_SELECTOR);
>
> vmx_dump_dtsel("IDTR:", GUEST_IDTR_LIMIT);
>
> vmx_dump_sel("TR: ", GUEST_TR_SELECTOR);
>
> - if ((vmexit_ctl & (VM_EXIT_SAVE_IA32_PAT | VM_EXIT_SAVE_IA32_EFER)) ||
>
> - (vmentry_ctl & (VM_ENTRY_LOAD_IA32_PAT | VM_ENTRY_LOAD_IA32_EFER)))
>
> - pr_err("EFER = 0x%016llx PAT = 0x%016llx\n",
>
> - vmcs_read64(GUEST_IA32_EFER),
>
> - vmcs_read64(GUEST_IA32_PAT));
>
> + if ((vmexit_ctl & VM_EXIT_SAVE_IA32_EFER) ||
>
>
Not your code, and completely benign since VM_EXIT_SAVE is never set, but I
>
don't like checking the VM_EXIT_SAVE_* flag as saving a field on VM-Exit has
>
zero impact on whether VM-Entry succeeds or fails. Same complaint on the PAT
>
field.
Added to v3.
>
> + (vmentry_ctl & VM_ENTRY_LOAD_IA32_EFER))
>
> + pr_err("EFER= 0x%016llx\n", vmcs_read64(GUEST_IA32_EFER));
>
>
Tying into the previous patch, I think we should print both the effective EFER
>
and vmcs.EFER. The effective EFER is relevant for several consistency checks.
>
Maybe something like this?
>
>
pr_err("EFER= 0x%016llx ", effective_efer);
>
if (vmentry_ctl & VM_ENTRY_LOAD_IA32_EFER)
>
pr_cont("vmcs.EFER= 0x%016llx\n", vmcs_read64(GUEST_IA32_EFER));
>
else
>
pr_cont("vmcs.EFER not loaded\n")
Added something similar, that makes it clear where the value came from,
in v3.
>
> + if ((vmexit_ctl & VM_EXIT_SAVE_IA32_PAT) ||
>
> + (vmentry_ctl & VM_ENTRY_LOAD_IA32_PAT))
>
> + pr_err("PAT = 0x%016llx\n", vmcs_read64(GUEST_IA32_PAT));
>
> pr_err("DebugCtl = 0x%016llx DebugExceptions = 0x%016lx\n",
>
> vmcs_read64(GUEST_IA32_DEBUGCTL),
>
> vmcs_readl(GUEST_PENDING_DBG_EXCEPTIONS));
>
> @@ -5846,10 +5847,10 @@ void dump_vmcs(void)
>
> vmcs_readl(HOST_IA32_SYSENTER_ESP),
>
> vmcs_read32(HOST_IA32_SYSENTER_CS),
>
> vmcs_readl(HOST_IA32_SYSENTER_EIP));
>
> - if (vmexit_ctl & (VM_EXIT_LOAD_IA32_PAT | VM_EXIT_LOAD_IA32_EFER))
>
> - pr_err("EFER = 0x%016llx PAT = 0x%016llx\n",
>
> - vmcs_read64(HOST_IA32_EFER),
>
> - vmcs_read64(HOST_IA32_PAT));
>
> + if (vmexit_ctl & VM_EXIT_LOAD_IA32_EFER)
>
> + pr_err("EFER= 0x%016llx\n", vmcs_read64(HOST_IA32_EFER));
>
> + if (vmexit_ctl & VM_EXIT_LOAD_IA32_PAT)
>
> + pr_err("PAT = 0x%016llx\n", vmcs_read64(HOST_IA32_PAT));
>
> if (cpu_has_load_perf_global_ctrl() &&
>
> vmexit_ctl & VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL)
>
> pr_err("PerfGlobCtl = 0x%016llx\n",
>
> --
>
> 2.30.0
>
>
dme.
--
And the sign said: long haired freaky people need not apply.