Merge branch kvm-arm64/pkvm-6.10 into kvmarm-master/next

* kvm-arm64/pkvm-6.10: (25 commits)
  : .
  : At last, a bunch of pKVM patches, courtesy of Fuad Tabba.
  : From the cover letter:
  :
  : "This series is a bit of a bombay-mix of patches we've been
  : carrying. There's no one overarching theme, but they do improve
  : the code by fixing existing bugs in pKVM, refactoring code to
  : make it more readable and easier to re-use for pKVM, or adding
  : functionality to the existing pKVM code upstream."
  : .
  KVM: arm64: Force injection of a data abort on NISV MMIO exit
  KVM: arm64: Restrict supported capabilities for protected VMs
  KVM: arm64: Refactor setting the return value in kvm_vm_ioctl_enable_cap()
  KVM: arm64: Document the KVM/arm64-specific calls in hypercalls.rst
  KVM: arm64: Rename firmware pseudo-register documentation file
  KVM: arm64: Reformat/beautify PTP hypercall documentation
  KVM: arm64: Clarify rationale for ZCR_EL1 value restored on guest exit
  KVM: arm64: Introduce and use predicates that check for protected VMs
  KVM: arm64: Add is_pkvm_initialized() helper
  KVM: arm64: Simplify vgic-v3 hypercalls
  KVM: arm64: Move setting the page as dirty out of the critical section
  KVM: arm64: Change kvm_handle_mmio_return() return polarity
  KVM: arm64: Fix comment for __pkvm_vcpu_init_traps()
  KVM: arm64: Prevent kmemleak from accessing .hyp.data
  KVM: arm64: Do not map the host fpsimd state to hyp in pKVM
  KVM: arm64: Rename __tlb_switch_to_{guest,host}() in VHE
  KVM: arm64: Support TLB invalidation in guest context
  KVM: arm64: Avoid BBM when changing only s/w bits in Stage-2 PTE
  KVM: arm64: Check for PTE validity when checking for executable/cacheable
  KVM: arm64: Avoid BUG-ing from the host abort path
  ...

Signed-off-by: Marc Zyngier <maz@kernel.org>

1 files changed, 91 insertions, 24 deletions

diff --git a/arch/arm64/kvm/hyp/nvhe/tlb.c b/arch/arm64/kvm/hyp/nvhe/tlb.c
index 2fc68da4036d..ca3c09df8d7c 100644
--- a/arch/arm64/kvm/hyp/nvhe/tlb.c
+++ b/arch/arm64/kvm/hyp/nvhe/tlb.c
@@ -11,13 +11,23 @@
 #include <nvhe/mem_protect.h>
 
 struct tlb_inv_context {
-	u64		tcr;
+	struct kvm_s2_mmu	*mmu;
+	u64			tcr;
+	u64			sctlr;
 };
 
-static void __tlb_switch_to_guest(struct kvm_s2_mmu *mmu,
-				  struct tlb_inv_context *cxt,
-				  bool nsh)
+static void enter_vmid_context(struct kvm_s2_mmu *mmu,
+			       struct tlb_inv_context *cxt,
+			       bool nsh)
 {
+	struct kvm_s2_mmu *host_s2_mmu = &host_mmu.arch.mmu;
+	struct kvm_cpu_context *host_ctxt;
+	struct kvm_vcpu *vcpu;
+
+	host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
+	vcpu = host_ctxt->__hyp_running_vcpu;
+	cxt->mmu = NULL;
+
 	/*
 	 * We have two requirements:
 	 *
@@ -40,20 +50,55 @@ static void __tlb_switch_to_guest(struct kvm_s2_mmu *mmu,
 	else
 		dsb(ish);
 
+	/*
+	 * If we're already in the desired context, then there's nothing to do.
+	 */
+	if (vcpu) {
+		/*
+		 * We're in guest context. However, for this to work, this needs
+		 * to be called from within __kvm_vcpu_run(), which ensures that
+		 * __hyp_running_vcpu is set to the current guest vcpu.
+		 */
+		if (mmu == vcpu->arch.hw_mmu || WARN_ON(mmu != host_s2_mmu))
+			return;
+
+		cxt->mmu = vcpu->arch.hw_mmu;
+	} else {
+		/* We're in host context. */
+		if (mmu == host_s2_mmu)
+			return;
+
+		cxt->mmu = host_s2_mmu;
+	}
+
 	if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
 		u64 val;
 
 		/*
 		 * For CPUs that are affected by ARM 1319367, we need to
-		 * avoid a host Stage-1 walk while we have the guest's
-		 * VMID set in the VTTBR in order to invalidate TLBs.
-		 * We're guaranteed that the S1 MMU is enabled, so we can
-		 * simply set the EPD bits to avoid any further TLB fill.
+		 * avoid a Stage-1 walk with the old VMID while we have
+		 * the new VMID set in the VTTBR in order to invalidate TLBs.
+		 * We're guaranteed that the host S1 MMU is enabled, so
+		 * we can simply set the EPD bits to avoid any further
+		 * TLB fill. For guests, we ensure that the S1 MMU is
+		 * temporarily enabled in the next context.
 		 */
 		val = cxt->tcr = read_sysreg_el1(SYS_TCR);
 		val |= TCR_EPD1_MASK | TCR_EPD0_MASK;
 		write_sysreg_el1(val, SYS_TCR);
 		isb();
+
+		if (vcpu) {
+			val = cxt->sctlr = read_sysreg_el1(SYS_SCTLR);
+			if (!(val & SCTLR_ELx_M)) {
+				val |= SCTLR_ELx_M;
+				write_sysreg_el1(val, SYS_SCTLR);
+				isb();
+			}
+		} else {
+			/* The host S1 MMU is always enabled. */
+			cxt->sctlr = SCTLR_ELx_M;
+		}
 	}
 
 	/*
@@ -62,18 +107,40 @@ static void __tlb_switch_to_guest(struct kvm_s2_mmu *mmu,
 	 * ensuring that we always have an ISB, but not two ISBs back
 	 * to back.
 	 */
-	__load_stage2(mmu, kern_hyp_va(mmu->arch));
+	if (vcpu)
+		__load_host_stage2();
+	else
+		__load_stage2(mmu, kern_hyp_va(mmu->arch));
+
 	asm(ALTERNATIVE("isb", "nop", ARM64_WORKAROUND_SPECULATIVE_AT));
 }
 
-static void __tlb_switch_to_host(struct tlb_inv_context *cxt)
+static void exit_vmid_context(struct tlb_inv_context *cxt)
 {
-	__load_host_stage2();
+	struct kvm_s2_mmu *mmu = cxt->mmu;
+	struct kvm_cpu_context *host_ctxt;
+	struct kvm_vcpu *vcpu;
+
+	host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
+	vcpu = host_ctxt->__hyp_running_vcpu;
+
+	if (!mmu)
+		return;
+
+	if (vcpu)
+		__load_stage2(mmu, kern_hyp_va(mmu->arch));
+	else
+		__load_host_stage2();
 
 	if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
-		/* Ensure write of the host VMID */
+		/* Ensure write of the old VMID */
 		isb();
-		/* Restore the host's TCR_EL1 */
+
+		if (!(cxt->sctlr & SCTLR_ELx_M)) {
+			write_sysreg_el1(cxt->sctlr, SYS_SCTLR);
+			isb();
+		}
+
 		write_sysreg_el1(cxt->tcr, SYS_TCR);
 	}
 }
@@ -84,7 +151,7 @@ void __kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu,
 	struct tlb_inv_context cxt;
 
 	/* Switch to requested VMID */
-	__tlb_switch_to_guest(mmu, &cxt, false);
+	enter_vmid_context(mmu, &cxt, false);
 
 	/*
 	 * We could do so much better if we had the VA as well.
@@ -105,7 +172,7 @@ void __kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu,
 	dsb(ish);
 	isb();
 
-	__tlb_switch_to_host(&cxt);
+	exit_vmid_context(&cxt);
 }
 
 void __kvm_tlb_flush_vmid_ipa_nsh(struct kvm_s2_mmu *mmu,
@@ -114,7 +181,7 @@ void __kvm_tlb_flush_vmid_ipa_nsh(struct kvm_s2_mmu *mmu,
 	struct tlb_inv_context cxt;
 
 	/* Switch to requested VMID */
-	__tlb_switch_to_guest(mmu, &cxt, true);
+	enter_vmid_context(mmu, &cxt, true);
 
 	/*
 	 * We could do so much better if we had the VA as well.
@@ -135,7 +202,7 @@ void __kvm_tlb_flush_vmid_ipa_nsh(struct kvm_s2_mmu *mmu,
 	dsb(nsh);
 	isb();
 
-	__tlb_switch_to_host(&cxt);
+	exit_vmid_context(&cxt);
 }
 
 void __kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
@@ -152,7 +219,7 @@ void __kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
 	start = round_down(start, stride);
 
 	/* Switch to requested VMID */
-	__tlb_switch_to_guest(mmu, &cxt, false);
+	enter_vmid_context(mmu, &cxt, false);
 
 	__flush_s2_tlb_range_op(ipas2e1is, start, pages, stride,
 				TLBI_TTL_UNKNOWN);
@@ -162,7 +229,7 @@ void __kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
 	dsb(ish);
 	isb();
 
-	__tlb_switch_to_host(&cxt);
+	exit_vmid_context(&cxt);
 }
 
 void __kvm_tlb_flush_vmid(struct kvm_s2_mmu *mmu)
@@ -170,13 +237,13 @@ void __kvm_tlb_flush_vmid(struct kvm_s2_mmu *mmu)
 	struct tlb_inv_context cxt;
 
 	/* Switch to requested VMID */
-	__tlb_switch_to_guest(mmu, &cxt, false);
+	enter_vmid_context(mmu, &cxt, false);
 
 	__tlbi(vmalls12e1is);
 	dsb(ish);
 	isb();
 
-	__tlb_switch_to_host(&cxt);
+	exit_vmid_context(&cxt);
 }
 
 void __kvm_flush_cpu_context(struct kvm_s2_mmu *mmu)
@@ -184,19 +251,19 @@ void __kvm_flush_cpu_context(struct kvm_s2_mmu *mmu)
 	struct tlb_inv_context cxt;
 
 	/* Switch to requested VMID */
-	__tlb_switch_to_guest(mmu, &cxt, false);
+	enter_vmid_context(mmu, &cxt, false);
 
 	__tlbi(vmalle1);
 	asm volatile("ic iallu");
 	dsb(nsh);
 	isb();
 
-	__tlb_switch_to_host(&cxt);
+	exit_vmid_context(&cxt);
 }
 
 void __kvm_flush_vm_context(void)
 {
-	/* Same remark as in __tlb_switch_to_guest() */
+	/* Same remark as in enter_vmid_context() */
 	dsb(ish);
 	__tlbi(alle1is);
 	dsb(ish);