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Peter Anvin" , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/8] KVM: x86/xen: Introduce kvm_xen_has_64bit_shinfo() macro Date: Fri, 5 Jun 2026 15:17:27 +0100 Message-ID: <20260605143034.3603-3-dwmw2@infradead.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260605143034.3603-1-dwmw2@infradead.org> References: <20260605143034.3603-1-dwmw2@infradead.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: David Woodhouse X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html From: David Woodhouse Add a kvm_xen_has_64bit_shinfo() helper macro to replace the repeated pattern of 'IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode' throughout the Xen emulation code. The macro uses READ_ONCE() to ensure a consistent snapshot of the flag, which can be changed by another vCPU at any time. This is the KVM equivalent of Xen's !has_32bit_shinfo(). Assisted-by: Kiro:claude-opus-4.6-1m Signed-off-by: David Woodhouse --- arch/x86/kvm/xen.c | 16 ++++++++-------- arch/x86/kvm/xen.h | 5 +++++ 2 files changed, 13 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index a7ab19f38b59..acd3cd87dd2f 100644 --- a/arch/x86/kvm/xen.c +++ b/arch/x86/kvm/xen.c @@ -72,7 +72,7 @@ static int kvm_xen_shared_info_init(struct kvm *kvm) BUILD_BUG_ON(offsetof(struct shared_info, wc) != 0xc00); BUILD_BUG_ON(offsetof(struct shared_info, wc_sec_hi) != 0xc0c); - if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) { + if (kvm_xen_has_64bit_shinfo(kvm)) { struct shared_info *shinfo = gpc->khva; wc_sec_hi = &shinfo->wc_sec_hi; @@ -390,7 +390,7 @@ static void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, bool atomic) BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, time) != sizeof(vx->runstate_times)); - if (IS_ENABLED(CONFIG_64BIT) && v->kvm->arch.xen.long_mode) { + if (kvm_xen_has_64bit_shinfo(v->kvm)) { user_len = sizeof(struct vcpu_runstate_info); times_ofs = offsetof(struct vcpu_runstate_info, state_entry_time); @@ -661,7 +661,7 @@ void kvm_xen_inject_pending_events(struct kvm_vcpu *v) } /* Now gpc->khva is a valid kernel address for the vcpu_info */ - if (IS_ENABLED(CONFIG_64BIT) && v->kvm->arch.xen.long_mode) { + if (kvm_xen_has_64bit_shinfo(v->kvm)) { struct vcpu_info *vi = gpc->khva; asm volatile(LOCK_PREFIX "orq %0, %1\n" @@ -978,7 +978,7 @@ int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data) * address, that's actually OK. kvm_xen_update_runstate_guest() * will cope. */ - if (IS_ENABLED(CONFIG_64BIT) && vcpu->kvm->arch.xen.long_mode) + if (kvm_xen_has_64bit_shinfo(vcpu->kvm)) sz = sizeof(struct vcpu_runstate_info); else sz = sizeof(struct compat_vcpu_runstate_info); @@ -1424,7 +1424,7 @@ static int kvm_xen_hypercall_complete_userspace(struct kvm_vcpu *vcpu) static inline int max_evtchn_port(struct kvm *kvm) { - if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) + if (kvm_xen_has_64bit_shinfo(kvm)) return EVTCHN_2L_NR_CHANNELS; else return COMPAT_EVTCHN_2L_NR_CHANNELS; @@ -1446,7 +1446,7 @@ static bool wait_pending_event(struct kvm_vcpu *vcpu, int nr_ports, goto out_rcu; ret = false; - if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) { + if (kvm_xen_has_64bit_shinfo(kvm)) { struct shared_info *shinfo = gpc->khva; pending_bits = (unsigned long *)&shinfo->evtchn_pending; } else { @@ -1820,7 +1820,7 @@ int kvm_xen_set_evtchn_fast(struct kvm_xen_evtchn *xe, struct kvm *kvm) if (!kvm_gpc_check(gpc, PAGE_SIZE)) goto out_rcu; - if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) { + if (kvm_xen_has_64bit_shinfo(kvm)) { struct shared_info *shinfo = gpc->khva; pending_bits = (unsigned long *)&shinfo->evtchn_pending; mask_bits = (unsigned long *)&shinfo->evtchn_mask; @@ -1861,7 +1861,7 @@ int kvm_xen_set_evtchn_fast(struct kvm_xen_evtchn *xe, struct kvm *kvm) goto out_rcu; } - if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) { + if (kvm_xen_has_64bit_shinfo(kvm)) { struct vcpu_info *vcpu_info = gpc->khva; if (!test_and_set_bit(port_word_bit, &vcpu_info->evtchn_pending_sel)) { WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1); diff --git a/arch/x86/kvm/xen.h b/arch/x86/kvm/xen.h index 59e6128a7bd3..3e8c9306eb89 100644 --- a/arch/x86/kvm/xen.h +++ b/arch/x86/kvm/xen.h @@ -248,6 +248,11 @@ struct compat_shared_info { #define COMPAT_EVTCHN_2L_NR_CHANNELS (8 * \ sizeof_field(struct compat_shared_info, \ evtchn_pending)) + +/* Latched VM-wide mode; the KVM equivalent of Xen's !has_32bit_shinfo(). */ +#define kvm_xen_has_64bit_shinfo(kvm) \ + (IS_ENABLED(CONFIG_64BIT) && READ_ONCE((kvm)->arch.xen.long_mode)) + struct compat_vcpu_runstate_info { int state; uint64_t state_entry_time; -- 2.54.0