LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Oliver Upton <oupton@google.com>
To: kvmarm@lists.cs.columbia.edu
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Paolo Bonzini <pbonzini@redhat.com>,
	Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Andy Lutomirski <luto@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	Peter Shier <pshier@google.com>,
	Shakeel Butt <shakeelb@google.com>,
	Guangyu Shi <guangyus@google.com>,
	Oliver Upton <oupton@google.com>
Subject: [PATCH v3 3/3] KVM: arm64: Use generic KVM xfer to guest work function
Date: Mon,  2 Aug 2021 19:28:09 +0000	[thread overview]
Message-ID: <20210802192809.1851010-4-oupton@google.com> (raw)
In-Reply-To: <20210802192809.1851010-1-oupton@google.com>

Clean up handling of checks for pending work by switching to the generic
infrastructure to do so.

We pick up handling for TIF_NOTIFY_RESUME from this switch, meaning that
task work will be correctly handled.

Signed-off-by: Oliver Upton <oupton@google.com>
---
 arch/arm64/kvm/Kconfig |  1 +
 arch/arm64/kvm/arm.c   | 72 ++++++++++++++++++++++++++----------------
 2 files changed, 45 insertions(+), 28 deletions(-)

diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index a4eba0908bfa..8bc1fac5fa26 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -26,6 +26,7 @@ menuconfig KVM
 	select HAVE_KVM_ARCH_TLB_FLUSH_ALL
 	select KVM_MMIO
 	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
+	select KVM_XFER_TO_GUEST_WORK
 	select SRCU
 	select KVM_VFIO
 	select HAVE_KVM_EVENTFD
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 60d0a546d7fd..8245efc6e88f 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -6,6 +6,7 @@
 
 #include <linux/bug.h>
 #include <linux/cpu_pm.h>
+#include <linux/entry-kvm.h>
 #include <linux/errno.h>
 #include <linux/err.h>
 #include <linux/kvm_host.h>
@@ -714,6 +715,45 @@ static bool vcpu_mode_is_bad_32bit(struct kvm_vcpu *vcpu)
 		static_branch_unlikely(&arm64_mismatched_32bit_el0);
 }
 
+/**
+ * kvm_vcpu_exit_request - returns true if the VCPU should *not* enter the guest
+ * @vcpu:	The VCPU pointer
+ * @ret:	Pointer to write optional return code
+ *
+ * Returns: true if the VCPU needs to return to a preemptible + interruptible
+ *	    and skip guest entry.
+ *
+ * This function disambiguates between two different types of exits: exits to a
+ * preemptible + interruptible kernel context and exits to userspace. For an
+ * exit to userspace, this function will write the return code to ret and return
+ * true. For an exit to preemptible + interruptible kernel context (i.e. check
+ * for pending work and re-enter), return true without writing to ret.
+ */
+static bool kvm_vcpu_exit_request(struct kvm_vcpu *vcpu, int *ret)
+{
+	struct kvm_run *run = vcpu->run;
+
+	/*
+	 * If we're using a userspace irqchip, then check if we need
+	 * to tell a userspace irqchip about timer or PMU level
+	 * changes and if so, exit to userspace (the actual level
+	 * state gets updated in kvm_timer_update_run and
+	 * kvm_pmu_update_run below).
+	 */
+	if (static_branch_unlikely(&userspace_irqchip_in_use)) {
+		if (kvm_timer_should_notify_user(vcpu) ||
+		    kvm_pmu_should_notify_user(vcpu)) {
+			*ret = -EINTR;
+			run->exit_reason = KVM_EXIT_INTR;
+			return true;
+		}
+	}
+
+	return kvm_request_pending(vcpu) ||
+			need_new_vmid_gen(&vcpu->arch.hw_mmu->vmid) ||
+			xfer_to_guest_mode_work_pending();
+}
+
 /**
  * kvm_arch_vcpu_ioctl_run - the main VCPU run function to execute guest code
  * @vcpu:	The VCPU pointer
@@ -757,7 +797,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 		/*
 		 * Check conditions before entering the guest
 		 */
-		cond_resched();
+		ret = xfer_to_guest_mode_handle_work(vcpu);
+		if (!ret)
+			ret = 1;
 
 		update_vmid(&vcpu->arch.hw_mmu->vmid);
 
@@ -776,31 +818,6 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 
 		kvm_vgic_flush_hwstate(vcpu);
 
-		/*
-		 * Exit if we have a signal pending so that we can deliver the
-		 * signal to user space.
-		 */
-		if (signal_pending(current)) {
-			ret = -EINTR;
-			run->exit_reason = KVM_EXIT_INTR;
-			++vcpu->stat.signal_exits;
-		}
-
-		/*
-		 * If we're using a userspace irqchip, then check if we need
-		 * to tell a userspace irqchip about timer or PMU level
-		 * changes and if so, exit to userspace (the actual level
-		 * state gets updated in kvm_timer_update_run and
-		 * kvm_pmu_update_run below).
-		 */
-		if (static_branch_unlikely(&userspace_irqchip_in_use)) {
-			if (kvm_timer_should_notify_user(vcpu) ||
-			    kvm_pmu_should_notify_user(vcpu)) {
-				ret = -EINTR;
-				run->exit_reason = KVM_EXIT_INTR;
-			}
-		}
-
 		/*
 		 * Ensure we set mode to IN_GUEST_MODE after we disable
 		 * interrupts and before the final VCPU requests check.
@@ -809,8 +826,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 		 */
 		smp_store_mb(vcpu->mode, IN_GUEST_MODE);
 
-		if (ret <= 0 || need_new_vmid_gen(&vcpu->arch.hw_mmu->vmid) ||
-		    kvm_request_pending(vcpu)) {
+		if (ret <= 0 || kvm_vcpu_exit_request(vcpu, &ret)) {
 			vcpu->mode = OUTSIDE_GUEST_MODE;
 			isb(); /* Ensure work in x_flush_hwstate is committed */
 			kvm_pmu_sync_hwstate(vcpu);
-- 
2.32.0.554.ge1b32706d8-goog


  parent reply	other threads:[~2021-08-02 19:28 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-02 19:28 [PATCH v3 0/3] KVM: arm64: Use generic guest entry infrastructure Oliver Upton
2021-08-02 19:28 ` [PATCH v3 1/3] KVM: arm64: Record number of signal exits as a vCPU stat Oliver Upton
2021-08-02 19:28 ` [PATCH v3 2/3] entry: KVM: Allow use of generic KVM entry w/o full generic support Oliver Upton
2021-08-02 19:28 ` Oliver Upton [this message]
2021-08-15  7:50 ` [PATCH v3 0/3] KVM: arm64: Use generic guest entry infrastructure Oliver Upton
2021-08-15  9:21   ` Marc Zyngier
2021-08-19 10:28 ` Marc Zyngier

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210802192809.1851010-4-oupton@google.com \
    --to=oupton@google.com \
    --cc=alexandru.elisei@arm.com \
    --cc=catalin.marinas@arm.com \
    --cc=guangyus@google.com \
    --cc=james.morse@arm.com \
    --cc=kvm@vger.kernel.org \
    --cc=kvmarm@lists.cs.columbia.edu \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=luto@kernel.org \
    --cc=maz@kernel.org \
    --cc=pbonzini@redhat.com \
    --cc=peterz@infradead.org \
    --cc=pshier@google.com \
    --cc=shakeelb@google.com \
    --cc=suzuki.poulose@arm.com \
    --cc=tglx@linutronix.de \
    --cc=will@kernel.org \
    --subject='Re: [PATCH v3 3/3] KVM: arm64: Use generic KVM xfer to guest work function' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).