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authorSean Christopherson <seanjc@google.com>2024-06-07 19:26:04 +0200
committerSean Christopherson <seanjc@google.com>2024-06-28 17:59:03 +0200
commitd83c36d822be44db4bad0c43bea99c8908f54117 (patch)
tree4f68948ed1ae17e495623266bbd51da924844fc0
parentKVM: VMX: Switch __vmx_exit() and kvm_x86_vendor_exit() in vmx_exit() (diff)
downloadlinux-d83c36d822be44db4bad0c43bea99c8908f54117.tar.xz
linux-d83c36d822be44db4bad0c43bea99c8908f54117.zip
KVM: nVMX: Add a helper to get highest pending from Posted Interrupt vector
Add a helper to retrieve the highest pending vector given a Posted Interrupt descriptor. While the actual operation is straightforward, it's surprisingly easy to mess up, e.g. if one tries to reuse lapic.c's find_highest_vector(), which doesn't work with PID.PIR due to the APIC's IRR and ISR component registers being physically discontiguous (they're 4-byte registers aligned at 16-byte intervals). To make PIR handling more consistent with respect to IRR and ISR handling, return -1 to indicate "no interrupt pending". Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240607172609.3205077-2-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
-rw-r--r--arch/x86/kvm/vmx/nested.c5
-rw-r--r--arch/x86/kvm/vmx/posted_intr.h10
2 files changed, 13 insertions, 2 deletions
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 643935a0f70a..8f4db6e8f57c 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -12,6 +12,7 @@
#include "mmu.h"
#include "nested.h"
#include "pmu.h"
+#include "posted_intr.h"
#include "sgx.h"
#include "trace.h"
#include "vmx.h"
@@ -3899,8 +3900,8 @@ static int vmx_complete_nested_posted_interrupt(struct kvm_vcpu *vcpu)
if (!pi_test_and_clear_on(vmx->nested.pi_desc))
return 0;
- max_irr = find_last_bit((unsigned long *)vmx->nested.pi_desc->pir, 256);
- if (max_irr != 256) {
+ max_irr = pi_find_highest_vector(vmx->nested.pi_desc);
+ if (max_irr > 0) {
vapic_page = vmx->nested.virtual_apic_map.hva;
if (!vapic_page)
goto mmio_needed;
diff --git a/arch/x86/kvm/vmx/posted_intr.h b/arch/x86/kvm/vmx/posted_intr.h
index 6b2a0226257e..1715d2ab07be 100644
--- a/arch/x86/kvm/vmx/posted_intr.h
+++ b/arch/x86/kvm/vmx/posted_intr.h
@@ -1,6 +1,8 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __KVM_X86_VMX_POSTED_INTR_H
#define __KVM_X86_VMX_POSTED_INTR_H
+
+#include <linux/find.h>
#include <asm/posted_intr.h>
void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu);
@@ -12,4 +14,12 @@ int vmx_pi_update_irte(struct kvm *kvm, unsigned int host_irq,
uint32_t guest_irq, bool set);
void vmx_pi_start_assignment(struct kvm *kvm);
+static inline int pi_find_highest_vector(struct pi_desc *pi_desc)
+{
+ int vec;
+
+ vec = find_last_bit((unsigned long *)pi_desc->pir, 256);
+ return vec < 256 ? vec : -1;
+}
+
#endif /* __KVM_X86_VMX_POSTED_INTR_H */