From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
x86@kernel.org, Jim Mattson <jmattson@google.com>,
Joerg Roedel <joro@8bytes.org>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Brijesh Singh <brijesh.singh@amd.com>
Subject: Re: [RFC PATCH 00/35] SEV-ES hypervisor support
Date: Mon, 30 Nov 2020 18:14:27 +0000 [thread overview]
Message-ID: <X8U2gyj7F2wFU3JI@google.com> (raw)
In-Reply-To: <60cbddaf-50f3-72ca-f673-ff0b421db3ad@redhat.com>
On Mon, Nov 30, 2020, Paolo Bonzini wrote:
> On 16/09/20 02:19, Sean Christopherson wrote:
> >
> > TDX also selectively blocks/skips portions of other ioctl()s so that the
> > TDX code itself can yell loudly if e.g. .get_cpl() is invoked. The event
> > injection restrictions are due to direct injection not being allowed (except
> > for NMIs); all IRQs have to be routed through APICv (posted interrupts) and
> > exception injection is completely disallowed.
> >
> > kvm_vcpu_ioctl_x86_get_vcpu_events:
> > if (!vcpu->kvm->arch.guest_state_protected)
> > events->interrupt.shadow = kvm_x86_ops.get_interrupt_shadow(vcpu);
>
> Perhaps an alternative implementation can enter the vCPU with immediate exit
> until no events are pending, and then return all zeroes?
This can't work. If the guest has STI blocking, e.g. it did STI->TDVMCALL with
a valid vIRQ in GUEST_RVI, then events->interrupt.shadow should technically be
non-zero to reflect the STI blocking. But, the immediate exit (a hardware IRQ
for TDX guests) will cause VM-Exit before the guest can execute any instructions
and thus the guest will never clear STI blocking and never consume the pending
event. Or there could be a valid vIRQ, but GUEST_RFLAGS.IF=0, in which case KVM
would need to run the guest for an indeterminate amount of time to wait for the
vIRQ to be consumed.
Tangentially related, I haven't looked through the official external TDX docs,
but I suspect that vmcs.GUEST_RVI is listed as inaccessible for production TDs.
This will be changed as the VMM needs access to GUEST_RVI to handle
STI->TDVMCALL(HLT), otherwise the VMM may incorrectly put the vCPU into a
blocked (not runnable) state even though it has a pending wake event.
next prev parent reply other threads:[~2020-11-30 18:15 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-14 20:15 [RFC PATCH 00/35] SEV-ES hypervisor support Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 01/35] KVM: SVM: Remove the call to sev_platform_status() during setup Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 02/35] KVM: SVM: Add support for SEV-ES capability in KVM Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 03/35] KVM: SVM: Add indirect access to the VM save area Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 04/35] KVM: SVM: Make GHCB accessor functions available to the hypervisor Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 05/35] KVM: SVM: Add initial support for SEV-ES GHCB access to KVM Tom Lendacky
[not found] ` <20200914205801.GA7084@sjchrist-ice>
2020-09-15 13:24 ` Tom Lendacky
2020-09-15 16:28 ` Sean Christopherson
2020-09-16 14:54 ` Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 06/35] KVM: SVM: Add required changes to support intercepts under SEV-ES Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 07/35] KVM: SVM: Modify DRx register intercepts for an SEV-ES guest Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 08/35] KVM: SVM: Prevent debugging under SEV-ES Tom Lendacky
2020-09-14 21:26 ` Sean Christopherson
2020-09-15 13:37 ` Tom Lendacky
2020-09-15 16:30 ` Sean Christopherson
2020-09-15 20:13 ` Tom Lendacky
2020-09-16 15:11 ` Tom Lendacky
2020-09-16 16:02 ` Sean Christopherson
2020-09-16 16:38 ` Tom Lendacky
2020-09-16 16:49 ` Sean Christopherson
2020-09-16 20:27 ` Tom Lendacky
2020-09-16 22:50 ` Sean Christopherson
2020-09-17 16:27 ` Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 09/35] KVM: SVM: Do not emulate MMIO " Tom Lendacky
2020-09-14 21:33 ` Sean Christopherson
2020-09-15 13:38 ` Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 10/35] KVM: SVM: Cannot re-initialize the VMCB after shutdown with SEV-ES Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 11/35] KVM: SVM: Prepare for SEV-ES exit handling in the sev.c file Tom Lendacky
[not found] ` <20200915172148.GE8420@sjchrist-ice>
2020-09-16 16:22 ` Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 12/35] KVM: SVM: Add initial support for a VMGEXIT VMEXIT Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 13/35] KVM: SVM: Create trace events for VMGEXIT processing Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 14/35] KVM: SVM: Add support for SEV-ES GHCB MSR protocol function 0x002 Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 15/35] KVM: SVM: Add support for SEV-ES GHCB MSR protocol function 0x004 Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 16/35] KVM: SVM: Add support for SEV-ES GHCB MSR protocol function 0x100 Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 17/35] KVM: SVM: Create trace events for VMGEXIT MSR protocol processing Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 18/35] KVM: SVM: Support MMIO for an SEV-ES guest Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 19/35] KVM: SVM: Support port IO operations " Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 20/35] KVM: SVM: Add SEV/SEV-ES support for intercepting INVD Tom Lendacky
2020-09-14 22:00 ` Sean Christopherson
2020-09-15 15:08 ` Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 21/35] KVM: SVM: Add support for EFER write traps for an SEV-ES guest Tom Lendacky
[not found] ` <20200914220800.GI7192@sjchrist-ice>
2020-09-15 15:45 ` Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 22/35] KVM: SVM: Add support for CR0 " Tom Lendacky
2020-09-14 22:13 ` Sean Christopherson
2020-09-15 15:56 ` Tom Lendacky
2020-11-30 18:15 ` Paolo Bonzini
2020-09-14 20:15 ` [RFC PATCH 23/35] KVM: SVM: Add support for CR4 " Tom Lendacky
2020-09-14 22:16 ` Sean Christopherson
2020-11-30 18:16 ` Paolo Bonzini
2020-09-14 20:15 ` [RFC PATCH 24/35] KVM: SVM: Add support for CR8 " Tom Lendacky
2020-09-14 22:19 ` Sean Christopherson
2020-09-15 15:57 ` Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 25/35] KVM: x86: Update __get_sregs() / __set_sregs() to support SEV-ES Tom Lendacky
2020-09-14 21:37 ` Sean Christopherson
2020-09-15 14:19 ` Tom Lendacky
2020-09-15 16:33 ` Sean Christopherson
2020-09-15 20:37 ` Tom Lendacky
2020-09-15 22:44 ` Sean Christopherson
2020-11-30 18:28 ` Paolo Bonzini
2020-11-30 19:39 ` Sean Christopherson
2020-09-14 20:15 ` [RFC PATCH 26/35] KVM: SVM: Guest FPU state save/restore not needed for SEV-ES guest Tom Lendacky
[not found] ` <20200914213917.GD7192@sjchrist-ice>
2020-09-15 14:25 ` Tom Lendacky
2020-09-15 16:34 ` Sean Christopherson
2020-09-14 20:15 ` [RFC PATCH 27/35] KVM: SVM: Add support for booting APs for an " Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 28/35] KVM: X86: Update kvm_skip_emulated_instruction() " Tom Lendacky
2020-09-14 21:51 ` Sean Christopherson
2020-09-15 14:57 ` Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 29/35] KVM: SVM: Add NMI support " Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 30/35] KVM: SVM: Set the encryption mask for the SVM host save area Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 31/35] KVM: SVM: Update ASID allocation to support SEV-ES guests Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 32/35] KVM: SVM: Provide support for SEV-ES vCPU creation/loading Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 33/35] KVM: SVM: Provide support for SEV-ES vCPU loading Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 34/35] KVM: SVM: Provide an updated VMRUN invocation for SEV-ES guests Tom Lendacky
2020-09-14 20:15 ` [RFC PATCH 35/35] KVM: SVM: Provide support to launch and run an SEV-ES guest Tom Lendacky
2020-09-14 22:59 ` [RFC PATCH 00/35] SEV-ES hypervisor support Sean Christopherson
2020-09-15 17:22 ` Tom Lendacky
2020-09-15 17:32 ` Sean Christopherson
2020-09-15 20:05 ` Brijesh Singh
2020-09-16 0:19 ` Sean Christopherson
2020-10-13 20:26 ` Tom Lendacky
2020-11-30 15:31 ` Paolo Bonzini
2020-11-30 16:06 ` Tom Lendacky
2020-11-30 18:18 ` Sean Christopherson
2020-11-30 18:14 ` Sean Christopherson [this message]
2020-11-30 18:35 ` Paolo Bonzini
2020-11-30 19:35 ` Sean Christopherson
2020-11-30 20:24 ` Paolo Bonzini
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