Re: [PATCH 03/26] KVM: arm64: Factor out stage 2 page table data from struct kvm

Having a go at reviewing. Might turn out to be more useful as a learning
exercise for me rather than useful feedback but we've got to start
somewhere..

-struct kvm_arch {
+struct kvm_s2_mmu {
 	struct kvm_vmid vmid;
 
-	/* stage2 entry level table */
-	pgd_t *pgd;
-	phys_addr_t pgd_phys;
-
-	/* VTCR_EL2 value for this VM */
-	u64    vtcr;
+	/*
+	 * stage2 entry level table
+	 *
+	 * Two kvm_s2_mmu structures in the same VM can point to the same pgd
+	 * here.  This happens when running a non-VHE guest hypervisor which
+	 * uses the canonical stage 2 page table for both vEL2 and for vEL1/0
+	 * with vHCR_EL2.VM == 0.
+	 */
+	pgd_t		*pgd;
+	phys_addr_t	pgd_phys;
 
 	/* The last vcpu id that ran on each physical CPU */
 	int __percpu *last_vcpu_ran;
 
+	struct kvm *kvm;
+};
+
+struct kvm_arch {
+	struct kvm_s2_mmu mmu;
+
+	/* VTCR_EL2 value for this VM */
+	u64    vtcr;

VTCR seems quite strongly tied to the MMU config. Is it not controlled
independently for the nested MMUs and so remains in this struct?

-static void stage2_dissolve_pmd(struct kvm *kvm, phys_addr_t addr, pmd_t *pmd)
+static void stage2_dissolve_pmd(struct kvm_s2_mmu *mmu, phys_addr_t addr, pmd_t *pmd)

How strictly is the long line style rule enforced? checkpatch has 16
such warnings on this patch.

-static void stage2_dissolve_pud(struct kvm *kvm, phys_addr_t addr, pud_t *pudp)
+static void stage2_dissolve_pud(struct kvm_s2_mmu *mmu, phys_addr_t addr, pud_t *pudp)
 {
+	struct kvm *kvm __maybe_unused = mmu->kvm;
+
 	if (!stage2_pud_huge(kvm, *pudp))
 		return;

There're a couple places with `__maybe_unused` on variables that are
then used soon after. Can they be dropped in these cases so as not to
hide legitimate warning?

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel