[v2,04/43] KVM: Force PPC to define its own rcuwait object

Message ID	20211009021236.4122790-5-seanjc@google.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <SRS0=s3kv=O5=lists.infradead.org=linux-riscv-bounces+linux-riscv=archiver.kernel.org@kernel.org> DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org DECC860FD7 Date: Fri, 8 Oct 2021 19:11:57 -0700 In-Reply-To: <20211009021236.4122790-1-seanjc@google.com> Message-Id: <20211009021236.4122790-5-seanjc@google.com> Mime-Version: 1.0 References: <20211009021236.4122790-1-seanjc@google.com> Subject: [PATCH v2 04/43] KVM: Force PPC to define its own rcuwait object From: Sean Christopherson <seanjc@google.com> To: Marc Zyngier <maz@kernel.org>, Huacai Chen <chenhuacai@kernel.org>, Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>, Paul Mackerras <paulus@ozlabs.org>, Anup Patel <anup.patel@wdc.com>, Paul Walmsley <paul.walmsley@sifive.com>, Palmer Dabbelt <palmer@dabbelt.com>, Albert Ou <aou@eecs.berkeley.edu>, Christian Borntraeger <borntraeger@de.ibm.com>, Janosch Frank <frankja@linux.ibm.com>, Paolo Bonzini <pbonzini@redhat.com> Cc: James Morse <james.morse@arm.com>, Alexandru Elisei <alexandru.elisei@arm.com>, Suzuki K Poulose <suzuki.poulose@arm.com>, Atish Patra <atish.patra@wdc.com>, David Hildenbrand <david@redhat.com>, Cornelia Huck <cohuck@redhat.com>, Claudio Imbrenda <imbrenda@linux.ibm.com>, Sean Christopherson <seanjc@google.com>, Vitaly Kuznetsov <vkuznets@redhat.com>, Wanpeng Li <wanpengli@tencent.com>, Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, David Matlack <dmatlack@google.com>, Oliver Upton <oupton@google.com>, Jing Zhang <jingzhangos@google.com> Precedence: list Reply-To: Sean Christopherson <seanjc@google.com> Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" <linux-riscv-bounces@lists.infradead.org> Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org
Series	KVM: Halt-polling and x86 APICv overhaul \| expand [v2,00/43] KVM: Halt-polling and x86 APICv overhaul [v2,01/43] KVM: VMX: Don't unblock vCPU w/ Posted IRQ if IRQs are disabled in guest [v2,02/43] KVM: SVM: Ensure target pCPU is read once when signalling AVIC doorbell [v2,03/43] KVM: s390: Ensure kvm_arch_no_poll() is read once when blocking vCPU [v2,04/43] KVM: Force PPC to define its own rcuwait object [v2,05/43] KVM: Update halt-polling stats if and only if halt-polling was attempted [v2,06/43] KVM: Refactor and document halt-polling stats update helper [v2,07/43] KVM: Reconcile discrepancies in halt-polling stats [v2,08/43] KVM: s390: Clear valid_wakeup in kvm_s390_handle_wait(), not in arch hook [v2,09/43] KVM: Drop obsolete kvm_arch_vcpu_block_finish() [v2,10/43] KVM: arm64: Move vGIC v4 handling for WFI out arch callback hook [v2,11/43] KVM: Don't block+unblock when halt-polling is successful [v2,12/43] KVM: x86: Tweak halt emulation helper names to free up kvm_vcpu_halt() [v2,13/43] KVM: Rename kvm_vcpu_block() => kvm_vcpu_halt() [v2,14/43] KVM: Split out a kvm_vcpu_block() helper from kvm_vcpu_halt() [v2,15/43] KVM: stats: Add stat to detect if vcpu is currently blocking [v2,16/43] KVM: Don't redo ktime_get() when calculating halt-polling stop/deadline [v2,17/43] KVM: x86: Directly block (instead of "halting") UNINITIALIZED vCPUs [v2,18/43] KVM: x86: Invoke kvm_vcpu_block() directly for non-HALTED wait states [v2,19/43] KVM: Add helpers to wake/query blocking vCPU [v2,20/43] KVM: VMX: Skip Posted Interrupt updates if APICv is hard disabled [v2,21/43] KVM: VMX: Clean up PI pre/post-block WARNs [v2,22/43] KVM: VMX: Drop unnecessary PI logic to handle impossible conditions [v2,23/43] KVM: VMX: Use boolean returns for Posted Interrupt "test" helpers [v2,24/43] KVM: VMX: Drop pointless PI.NDST update when blocking [v2,25/43] KVM: VMX: Save/restore IRQs (instead of CLI/STI) during PI pre/post block [v2,26/43] KVM: VMX: Read Posted Interrupt "control" exactly once per loop iteration [v2,27/43] KVM: VMX: Move Posted Interrupt ndst computation out of write loop [v2,28/43] KVM: VMX: Remove vCPU from PI wakeup list before updating PID.NV [v2,29/43] KVM: VMX: Handle PI wakeup shenanigans during vcpu_put/load [v2,30/43] KVM: Drop unused kvm_vcpu.pre_pcpu field [v2,31/43] KVM: Move x86 VMX's posted interrupt list_head to vcpu_vmx [v2,32/43] KVM: VMX: Move preemption timer <=> hrtimer dance to common x86 [v2,33/43] KVM: x86: Unexport LAPIC's switch_to_{hv, sw}_timer() helpers [v2,34/43] KVM: x86: Remove defunct pre_block/post_block kvm_x86_ops hooks [v2,35/43] KVM: SVM: Signal AVIC doorbell iff vCPU is in guest mode [v2,36/43] KVM: SVM: Don't bother checking for "running" AVIC when kicking for IPIs [v2,37/43] KVM: SVM: Unconditionally mark AVIC as running on vCPU load (with APICv) [v2,38/43] KVM: Drop defunct kvm_arch_vcpu_(un)blocking() hooks [v2,39/43] KVM: VMX: Don't do full kick when triggering posted interrupt "fails" [v2,40/43] KVM: VMX: Wake vCPU when delivering posted IRQ even if vCPU == this vCPU [v2,41/43] KVM: VMX: Pass desired vector instead of bool for triggering posted IRQ [v2,42/43] KVM: VMX: Fold fallback path into triggering posted IRQ helper [v2,43/43] KVM: VMX: Don't do full kick when handling posted interrupt wakeup

Message ID

20211009021236.4122790-5-seanjc@google.com (mailing list archive)

State

New, archived

Headers

DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org DECC860FD7
Date: Fri,  8 Oct 2021 19:11:57 -0700
In-Reply-To: <20211009021236.4122790-1-seanjc@google.com>
Message-Id: <20211009021236.4122790-5-seanjc@google.com>
Mime-Version: 1.0
References: <20211009021236.4122790-1-seanjc@google.com>
Subject: [PATCH v2 04/43] KVM: Force PPC to define its own rcuwait object
From: Sean Christopherson <seanjc@google.com>
To: Marc Zyngier <maz@kernel.org>, Huacai Chen <chenhuacai@kernel.org>,
 Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>,
 Paul Mackerras <paulus@ozlabs.org>,
 Anup Patel <anup.patel@wdc.com>, Paul Walmsley <paul.walmsley@sifive.com>,
 Palmer Dabbelt <palmer@dabbelt.com>, Albert Ou <aou@eecs.berkeley.edu>,
 Christian Borntraeger <borntraeger@de.ibm.com>,
 Janosch Frank <frankja@linux.ibm.com>, Paolo Bonzini <pbonzini@redhat.com>
Cc: James Morse <james.morse@arm.com>,
 Alexandru Elisei <alexandru.elisei@arm.com>,
 Suzuki K Poulose <suzuki.poulose@arm.com>, Atish Patra <atish.patra@wdc.com>,
 David Hildenbrand <david@redhat.com>, Cornelia Huck <cohuck@redhat.com>,
 Claudio Imbrenda <imbrenda@linux.ibm.com>,
 Sean Christopherson <seanjc@google.com>,
 Vitaly Kuznetsov <vkuznets@redhat.com>, Wanpeng Li <wanpengli@tencent.com>,
 Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
 linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu,
 linux-mips@vger.kernel.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org,
 kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org,
 linux-kernel@vger.kernel.org, David Matlack <dmatlack@google.com>,
 Oliver Upton <oupton@google.com>, Jing Zhang <jingzhangos@google.com>
Precedence: list
Reply-To: Sean Christopherson <seanjc@google.com>
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Sender: "linux-riscv" <linux-riscv-bounces@lists.infradead.org>
Errors-To: 
 linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org

Series

KVM: Halt-polling and x86 APICv overhaul | expand

Commit Message

Sean Christopherson Oct. 9, 2021, 2:11 a.m. UTC

Do not define/reference kvm_vcpu.wait if __KVM_HAVE_ARCH_WQP is true, and
instead force the architecture (PPC) to define its own rcuwait object.
Allowing common KVM to directly access vcpu->wait without a guard makes
it all too easy to introduce potential bugs, e.g. kvm_vcpu_block(),
kvm_vcpu_on_spin(), and async_pf_execute() all operate on vcpu->wait, not
the result of kvm_arch_vcpu_get_wait(), and so may do the wrong thing for
PPC.

Due to PPC's shenanigans with respect to callbacks and waits (it switches
to the virtual core's wait object at KVM_RUN!?!?), it's not clear whether
or not this fixes any bugs.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/powerpc/include/asm/kvm_host.h | 1 +
 arch/powerpc/kvm/powerpc.c          | 3 ++-
 include/linux/kvm_host.h            | 2 ++
 virt/kvm/async_pf.c                 | 2 +-
 virt/kvm/kvm_main.c                 | 9 ++++++---
 5 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 59cb38b04ede..876c10803cda 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -749,6 +749,7 @@  struct kvm_vcpu_arch {
 	u8 irq_pending; /* Used by XIVE to signal pending guest irqs */
 	u32 last_inst;
 
+	struct rcuwait wait;
 	struct rcuwait *waitp;
 	struct kvmppc_vcore *vcore;
 	int ret;
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 8ab90ce8738f..be22da157569 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -762,7 +762,8 @@  int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 	if (err)
 		goto out_vcpu_uninit;
 
-	vcpu->arch.waitp = &vcpu->wait;
+	rcuwait_init(&vcpu->arch.wait);
+	vcpu->arch.waitp = &vcpu->arch.wait;
 	kvmppc_create_vcpu_debugfs(vcpu, vcpu->vcpu_id);
 	return 0;
 
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 60a35d9fe259..1ced2914d9ca 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -310,7 +310,9 @@  struct kvm_vcpu {
 	struct mutex mutex;
 	struct kvm_run *run;
 
+#ifndef __KVM_HAVE_ARCH_WQP
 	struct rcuwait wait;
+#endif
 	struct pid __rcu *pid;
 	int sigset_active;
 	sigset_t sigset;
diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
index dd777688d14a..ccb35c22785e 100644
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -85,7 +85,7 @@  static void async_pf_execute(struct work_struct *work)
 
 	trace_kvm_async_pf_completed(addr, cr2_or_gpa);
 
-	rcuwait_wake_up(&vcpu->wait);
+	rcuwait_wake_up(kvm_arch_vcpu_get_wait(vcpu));
 
 	mmput(mm);
 	kvm_put_kvm(vcpu->kvm);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 7bc38549487e..5d4a90032277 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -421,7 +421,9 @@  static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
 	vcpu->kvm = kvm;
 	vcpu->vcpu_id = id;
 	vcpu->pid = NULL;
+#ifndef __KVM_HAVE_ARCH_WQP
 	rcuwait_init(&vcpu->wait);
+#endif
 	kvm_async_pf_vcpu_init(vcpu);
 
 	vcpu->pre_pcpu = -1;
@@ -3213,6 +3215,7 @@  update_halt_poll_stats(struct kvm_vcpu *vcpu, u64 poll_ns, bool waited)
  */
 void kvm_vcpu_block(struct kvm_vcpu *vcpu)
 {
+	struct rcuwait *wait = kvm_arch_vcpu_get_wait(vcpu);
 	bool halt_poll_allowed = !kvm_arch_no_poll(vcpu);
 	ktime_t start, cur, poll_end;
 	bool waited = false;
@@ -3251,7 +3254,7 @@  void kvm_vcpu_block(struct kvm_vcpu *vcpu)
 	}
 
 
-	prepare_to_rcuwait(&vcpu->wait);
+	prepare_to_rcuwait(wait);
 	for (;;) {
 		set_current_state(TASK_INTERRUPTIBLE);
 
@@ -3261,7 +3264,7 @@  void kvm_vcpu_block(struct kvm_vcpu *vcpu)
 		waited = true;
 		schedule();
 	}
-	finish_rcuwait(&vcpu->wait);
+	finish_rcuwait(wait);
 	cur = ktime_get();
 	if (waited) {
 		vcpu->stat.generic.halt_wait_ns +=
@@ -3460,7 +3463,7 @@  void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode)
 				continue;
 			if (vcpu == me)
 				continue;
-			if (rcuwait_active(&vcpu->wait) &&
+			if (rcuwait_active(kvm_arch_vcpu_get_wait(vcpu)) &&
 			    !vcpu_dy_runnable(vcpu))
 				continue;
 			if (READ_ONCE(vcpu->preempted) && yield_to_kernel_mode &&

[v2,04/43] KVM: Force PPC to define its own rcuwait object

Commit Message

Patch