From: "Radim Krčmář" <rkrcmar@redhat.com>
To: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Cc: pbonzini@redhat.com, joro@8bytes.org, bp@alien8.de,
gleb@kernel.org, alex.williamson@redhat.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, wei@redhat.com,
sherry.hurwitz@amd.com
Subject: Re: [PART1 RFC v2 07/10] svm: Add VMEXIT handlers for AVIC
Date: Wed, 9 Mar 2016 21:55:13 +0100 [thread overview]
Message-ID: <20160309205512.GD19459@potion.brq.redhat.com> (raw)
In-Reply-To: <1457124368-2025-8-git-send-email-Suravee.Suthikulpanit@amd.com>
2016-03-04 14:46-0600, Suravee Suthikulpanit:
> From: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
>
> Introduce VMEXIT handlers, avic_incp_ipi_interception() and
> avic_noaccel_interception().
>
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> ---
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> @@ -3690,6 +3690,264 @@ static int mwait_interception(struct vcpu_svm *svm)
> + case AVIC_INCMP_IPI_ERR_TARGET_NOT_RUN: {
> + kvm_for_each_vcpu(i, vcpu, kvm) {
> + if (!kvm_apic_match_dest(vcpu, apic,
> + icrl & APIC_SHORT_MASK,
> + GET_APIC_DEST_FIELD(icrh),
> + icrl & APIC_DEST_MASK))
> + continue;
> +
> + kvm_vcpu_kick(vcpu);
KVM shouldn't kick VCPUs that are running. (Imagine a broadcast when
most VCPUs are in guest mode.)
I think a new helper might be useful here: we only want to wake up from
wait queue, but never force VCPU out of guest mode ... kvm_vcpu_kick()
does both.
> +static int avic_noaccel_trap_write(struct vcpu_svm *svm)
> +{
> + switch (offset) {
> + case APIC_ID: {
> + case APIC_LDR: {
> + case APIC_DFR: {
> + }
It's not enough to modify the AVIC map here. Userspace can also change
the APIC page with kvm_vcpu_ioctl_set_lapic, so AVIC would better hook
into some common path.
I think that AVIC map should be connected to recalculate_apic_map() and
'struct kvm_apic_map' as we already have the mode and a coupling of
LAPICs and VCPUs there.
recalculate_apic_map() is currently quite wasteful as it recomputes the
whole map on every change, but its simplicity should be bearable.
> +static int avic_noaccel_interception(struct vcpu_svm *svm)
> +{
> + int ret = 0;
> + u32 offset = svm->vmcb->control.exit_info_1 & 0xFF0;
> + u32 rw = (svm->vmcb->control.exit_info_1 >> 32) & 0x1;
Change "u32 rw" to "bool write"
> + u32 vector = svm->vmcb->control.exit_info_2 & 0xFFFFFFFF;
and please #define those masks.
> + pr_debug("%s: offset=%#x, rw=%#x, vector=%#x, vcpu_id=%#x, cpu=%#x\n",
> + __func__, offset, rw, vector, svm->vcpu.vcpu_id, svm->vcpu.cpu);
> +
> + BUG_ON(offset >= 0x400);
These are valid faulting registers, so our implementation has to handle
them. (And the rule is to never BUG if a recovery is simple.)
> + switch (offset) {
> + case APIC_ID:
> + case APIC_EOI:
> + case APIC_RRR:
> + case APIC_LDR:
> + case APIC_DFR:
> + case APIC_SPIV:
> + case APIC_ESR:
> + case APIC_ICR:
> + case APIC_LVTT:
> + case APIC_LVTTHMR:
> + case APIC_LVTPC:
> + case APIC_LVT0:
> + case APIC_LVT1:
> + case APIC_LVTERR:
> + case APIC_TMICT:
> + case APIC_TDCR: {
(Try a helper that returns true/false for trap/fault registers, the code
might look nicer.)
> + /* Handling Trap */
> + if (!rw) /* Trap read should never happens */
> + BUG();
> + ret = avic_noaccel_trap_write(svm);
> + break;
> + }
> + default: {
> + /* Handling Fault */
> + if (rw)
> + ret = avic_noaccel_fault_write(svm);
> + else
> + ret = avic_noaccel_fault_read(svm);
> + skip_emulated_instruction(&svm->vcpu);
AVIC doesn't tell us what it wanted to write, so KVM has to emulate the
instruction.
next prev parent reply other threads:[~2016-03-09 20:55 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-04 20:45 [PART1 RFC v2 00/10] KVM: x86: Introduce SVM AVIC support Suravee Suthikulpanit
2016-03-04 20:45 ` [PART1 RFC v2 01/10] KVM: x86: Misc LAPIC changes to exposes helper functions Suravee Suthikulpanit
2016-03-04 20:46 ` [PART1 RFC v2 02/10] KVM: x86: Introducing kvm_x86_ops VCPU blocking/unblocking Suravee Suthikulpanit
2016-03-07 15:42 ` Paolo Bonzini
2016-03-14 6:19 ` Suravee Suthikulpanit
2016-03-04 20:46 ` [PART1 RFC v2 03/10] svm: Introduce new AVIC VMCB registers Suravee Suthikulpanit
2016-03-07 15:44 ` Paolo Bonzini
2016-03-14 7:41 ` Suravee Suthikulpanit
2016-03-14 12:25 ` Paolo Bonzini
2016-03-15 12:51 ` Suravee Suthikulpanit
2016-03-04 20:46 ` [PART1 RFC v2 04/10] svm: clean up V_TPR, V_IRQ, V_INTR_PRIO, and V_INTR_MASKING Suravee Suthikulpanit
2016-03-04 20:46 ` [PART1 RFC v2 05/10] KVM: x86: Detect and Initialize AVIC support Suravee Suthikulpanit
2016-03-07 16:41 ` Paolo Bonzini
2016-03-15 17:09 ` Suravee Suthikulpanit
2016-03-15 17:22 ` Paolo Bonzini
2016-03-16 6:22 ` Suravee Suthikulpanit
2016-03-16 7:20 ` Paolo Bonzini
2016-03-16 8:21 ` Suravee Suthikulpanit
2016-03-16 11:12 ` Paolo Bonzini
2016-03-04 20:46 ` [PART1 RFC v2 06/10] svm: Add interrupt injection via AVIC Suravee Suthikulpanit
2016-03-07 15:36 ` Paolo Bonzini
2016-03-08 21:54 ` Radim Krčmář
2016-03-09 11:10 ` Paolo Bonzini
2016-03-09 16:00 ` Radim Krčmář
2016-03-14 9:41 ` Suravee Suthikulpanit
2016-03-14 12:27 ` Paolo Bonzini
2016-03-14 9:50 ` Suravee Suthikulpanit
2016-03-14 5:25 ` Suravee Suthikulpanit
2016-03-14 8:54 ` Suravee Suthikulpanit
2016-03-04 20:46 ` [PART1 RFC v2 07/10] svm: Add VMEXIT handlers for AVIC Suravee Suthikulpanit
2016-03-07 15:58 ` Paolo Bonzini
2016-03-08 22:05 ` Radim Krčmář
2016-03-09 10:56 ` Paolo Bonzini
2016-03-09 20:55 ` Radim Krčmář [this message]
2016-03-10 19:34 ` Radim Krčmář
2016-03-10 19:54 ` Paolo Bonzini
2016-03-10 20:44 ` Radim Krčmář
2016-03-17 3:58 ` Suravee Suthikulpanit
2016-03-17 9:35 ` Paolo Bonzini
2016-03-17 19:44 ` Suravee Suthikulpanit
2016-03-17 20:27 ` [PATCH] KVM: split kvm_vcpu_wake_up from kvm_vcpu_kick Radim Krčmář
2016-03-18 5:13 ` Suravee Suthikulpanit
2016-03-04 20:46 ` [PART1 RFC v2 08/10] svm: Do not expose x2APIC when enable AVIC Suravee Suthikulpanit
2016-03-04 20:46 ` [PART1 RFC v2 09/10] svm: Do not intercept CR8 " Suravee Suthikulpanit
2016-03-07 15:39 ` Paolo Bonzini
2016-03-14 6:09 ` Suravee Suthikulpanit
2016-03-14 12:28 ` Paolo Bonzini
2016-03-04 20:46 ` [PART1 RFC v2 10/10] svm: Manage vcpu load/unload " Suravee Suthikulpanit
2016-03-09 21:46 ` Radim Krčmář
2016-03-10 14:01 ` Radim Krčmář
2016-03-14 11:58 ` Suravee Suthikulpanit
2016-03-14 16:54 ` Radim Krčmář
2016-03-14 11:48 ` Suravee Suthikulpanit
2016-03-14 16:40 ` Radim Krčmář
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