Merge tag 'kvmarm-fixes-5.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into kvm-master

KVM/arm fixes for Linux 5.7, take #2

- Fix compilation with Clang
- Correctly initialize GICv4.1 in the absence of a virtual ITS
- Move SP_EL0 save/restore to the guest entry/exit code
- Handle PC wrap around on 32bit guests, and narrow all 32bit
  registers on userspace access

4 files changed, 33 insertions, 15 deletions

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 23ebe51410f0..50a279d3ddd7 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -200,6 +200,13 @@ static int set_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	}
 
 	memcpy((u32 *)regs + off, valp, KVM_REG_SIZE(reg->id));
+
+	if (*vcpu_cpsr(vcpu) & PSR_MODE32_BIT) {
+		int i;
+
+		for (i = 0; i < 16; i++)
+			*vcpu_reg32(vcpu, i) = (u32)*vcpu_reg32(vcpu, i);
+	}
 out:
 	return err;
 }
diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index d22d0534dd60..90186cf6473e 100644
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -18,6 +18,7 @@
 
 #define CPU_GP_REG_OFFSET(x)	(CPU_GP_REGS + x)
 #define CPU_XREG_OFFSET(x)	CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 8*x)
+#define CPU_SP_EL0_OFFSET	(CPU_XREG_OFFSET(30) + 8)
 
 	.text
 	.pushsection	.hyp.text, "ax"
@@ -47,6 +48,16 @@
 	ldp	x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]
 .endm
 
+.macro save_sp_el0 ctxt, tmp
+	mrs	\tmp,	sp_el0
+	str	\tmp,	[\ctxt, #CPU_SP_EL0_OFFSET]
+.endm
+
+.macro restore_sp_el0 ctxt, tmp
+	ldr	\tmp,	  [\ctxt, #CPU_SP_EL0_OFFSET]
+	msr	sp_el0, \tmp
+.endm
+
 /*
  * u64 __guest_enter(struct kvm_vcpu *vcpu,
  *		     struct kvm_cpu_context *host_ctxt);
@@ -60,6 +71,9 @@ SYM_FUNC_START(__guest_enter)
 	// Store the host regs
 	save_callee_saved_regs x1
 
+	// Save the host's sp_el0
+	save_sp_el0	x1, x2
+
 	// Now the host state is stored if we have a pending RAS SError it must
 	// affect the host. If any asynchronous exception is pending we defer
 	// the guest entry. The DSB isn't necessary before v8.2 as any SError
@@ -83,6 +97,9 @@ alternative_else_nop_endif
 	// when this feature is enabled for kernel code.
 	ptrauth_switch_to_guest x29, x0, x1, x2
 
+	// Restore the guest's sp_el0
+	restore_sp_el0 x29, x0
+
 	// Restore guest regs x0-x17
 	ldp	x0, x1,   [x29, #CPU_XREG_OFFSET(0)]
 	ldp	x2, x3,   [x29, #CPU_XREG_OFFSET(2)]
@@ -130,6 +147,9 @@ SYM_INNER_LABEL(__guest_exit, SYM_L_GLOBAL)
 	// Store the guest regs x18-x29, lr
 	save_callee_saved_regs x1
 
+	// Store the guest's sp_el0
+	save_sp_el0	x1, x2
+
 	get_host_ctxt	x2, x3
 
 	// Macro ptrauth_switch_to_guest format:
@@ -139,6 +159,9 @@ SYM_INNER_LABEL(__guest_exit, SYM_L_GLOBAL)
 	// when this feature is enabled for kernel code.
 	ptrauth_switch_to_host x1, x2, x3, x4, x5
 
+	// Restore the hosts's sp_el0
+	restore_sp_el0 x2, x3
+
 	// Now restore the host regs
 	restore_callee_saved_regs x2
 
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index c2a13ab3c471..9c5cfb04170e 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -198,7 +198,6 @@ SYM_CODE_END(__hyp_panic)
 .macro invalid_vector	label, target = __hyp_panic
 	.align	2
 SYM_CODE_START(\label)
-\label:
 	b \target
 SYM_CODE_END(\label)
 .endm
diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
index 75b1925763f1..6d2df9fe0b5d 100644
--- a/arch/arm64/kvm/hyp/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/sysreg-sr.c
@@ -15,8 +15,9 @@
 /*
  * Non-VHE: Both host and guest must save everything.
  *
- * VHE: Host and guest must save mdscr_el1 and sp_el0 (and the PC and pstate,
- * which are handled as part of the el2 return state) on every switch.
+ * VHE: Host and guest must save mdscr_el1 and sp_el0 (and the PC and
+ * pstate, which are handled as part of the el2 return state) on every
+ * switch (sp_el0 is being dealt with in the assembly code).
  * tpidr_el0 and tpidrro_el0 only need to be switched when going
  * to host userspace or a different VCPU.  EL1 registers only need to be
  * switched when potentially going to run a different VCPU.  The latter two
@@ -26,12 +27,6 @@
 static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
 {
 	ctxt->sys_regs[MDSCR_EL1]	= read_sysreg(mdscr_el1);
-
-	/*
-	 * The host arm64 Linux uses sp_el0 to point to 'current' and it must
-	 * therefore be saved/restored on every entry/exit to/from the guest.
-	 */
-	ctxt->gp_regs.regs.sp		= read_sysreg(sp_el0);
 }
 
 static void __hyp_text __sysreg_save_user_state(struct kvm_cpu_context *ctxt)
@@ -99,12 +94,6 @@ NOKPROBE_SYMBOL(sysreg_save_guest_state_vhe);
 static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctxt)
 {
 	write_sysreg(ctxt->sys_regs[MDSCR_EL1],	  mdscr_el1);
-
-	/*
-	 * The host arm64 Linux uses sp_el0 to point to 'current' and it must
-	 * therefore be saved/restored on every entry/exit to/from the guest.
-	 */
-	write_sysreg(ctxt->gp_regs.regs.sp,	  sp_el0);
 }
 
 static void __hyp_text __sysreg_restore_user_state(struct kvm_cpu_context *ctxt)