linux-kernel - [PATCH V3 10/10] arm64: KVM: add guest SEA support

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Message-Id: <1475875882-2604-11-git-send-email-tbaicar@codeaurora.org>
Date:   Fri,  7 Oct 2016 15:31:22 -0600
From:   Tyler Baicar <tbaicar@...eaurora.org>
To:     christoffer.dall@...aro.org, marc.zyngier@....com,
        pbonzini@...hat.com, rkrcmar@...hat.com, linux@...linux.org.uk,
        catalin.marinas@....com, will.deacon@....com, rjw@...ysocki.net,
        lenb@...nel.org, matt@...eblueprint.co.uk, robert.moore@...el.com,
        lv.zheng@...el.com, mark.rutland@....com, james.morse@....com,
        akpm@...ux-foundation.org, sandeepa.s.prabhu@...il.com,
        shijie.huang@....com, paul.gortmaker@...driver.com,
        tomasz.nowicki@...aro.org, fu.wei@...aro.org, rostedt@...dmis.org,
        bristot@...hat.com, linux-arm-kernel@...ts.infradead.org,
        kvmarm@...ts.cs.columbia.edu, Dkvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
        linux-efi@...r.kernel.org, devel@...ica.org
Cc:     Tyler Baicar <tbaicar@...eaurora.org>
Subject: [PATCH V3 10/10] arm64: KVM: add guest SEA support

Currently external aborts are unsupported by the guest abort
handling. Add handling for SEAs so that the host kernel reports
SEAs which occur in the guest kernel.

Signed-off-by: Tyler Baicar <tbaicar@...eaurora.org>
---
 arch/arm/include/asm/kvm_arm.h       |  1 +
 arch/arm/include/asm/system_misc.h   |  5 +++++
 arch/arm/kvm/mmu.c                   | 15 +++++++++++++--
 arch/arm64/include/asm/kvm_arm.h     |  1 +
 arch/arm64/include/asm/system_misc.h |  2 ++
 arch/arm64/mm/fault.c                | 13 +++++++++++++
 6 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/arch/arm/include/asm/kvm_arm.h b/arch/arm/include/asm/kvm_arm.h
index e22089f..33a77509 100644
--- a/arch/arm/include/asm/kvm_arm.h
+++ b/arch/arm/include/asm/kvm_arm.h
@@ -187,6 +187,7 @@
 #define FSC_FAULT	(0x04)
 #define FSC_ACCESS	(0x08)
 #define FSC_PERM	(0x0c)
+#define FSC_EXTABT	(0x10)
 
 /* Hyp Prefetch Fault Address Register (HPFAR/HDFAR) */
 #define HPFAR_MASK	(~0xf)
diff --git a/arch/arm/include/asm/system_misc.h b/arch/arm/include/asm/system_misc.h
index a3d61ad..86e1faa 100644
--- a/arch/arm/include/asm/system_misc.h
+++ b/arch/arm/include/asm/system_misc.h
@@ -24,4 +24,9 @@ extern unsigned int user_debug;
 
 #endif /* !__ASSEMBLY__ */
 
+inline int handle_guest_sea(unsigned long addr, unsigned int esr)
+{
+	return -1;
+}
+
 #endif /* __ASM_ARM_SYSTEM_MISC_H */
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index e9a5c0e..24cde84 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -29,6 +29,7 @@
 #include <asm/kvm_asm.h>
 #include <asm/kvm_emulate.h>
 #include <asm/virt.h>
+#include <asm/system_misc.h>
 
 #include "trace.h"
 
@@ -1441,8 +1442,18 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run)
 
 	/* Check the stage-2 fault is trans. fault or write fault */
 	fault_status = kvm_vcpu_trap_get_fault_type(vcpu);
-	if (fault_status != FSC_FAULT && fault_status != FSC_PERM &&
-	    fault_status != FSC_ACCESS) {
+
+	if (fault_status == FSC_EXTABT) {
+		if(handle_guest_sea((unsigned long)fault_ipa,
+				    kvm_vcpu_get_hsr(vcpu))) {
+			kvm_err("Failed to handle guest SEA, FSC: EC=%#x xFSC=%#lx ESR_EL2=%#lx\n",
+				kvm_vcpu_trap_get_class(vcpu),
+				(unsigned long)kvm_vcpu_trap_get_fault(vcpu),
+				(unsigned long)kvm_vcpu_get_hsr(vcpu));
+			return -EFAULT;
+		}
+	} else if (fault_status != FSC_FAULT && fault_status != FSC_PERM &&
+		   fault_status != FSC_ACCESS) {
 		kvm_err("Unsupported FSC: EC=%#x xFSC=%#lx ESR_EL2=%#lx\n",
 			kvm_vcpu_trap_get_class(vcpu),
 			(unsigned long)kvm_vcpu_trap_get_fault(vcpu),
diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index 4b5c977..be0efb6 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -201,6 +201,7 @@
 #define FSC_FAULT	ESR_ELx_FSC_FAULT
 #define FSC_ACCESS	ESR_ELx_FSC_ACCESS
 #define FSC_PERM	ESR_ELx_FSC_PERM
+#define FSC_EXTABT	ESR_ELx_FSC_EXTABT
 
 /* Hyp Prefetch Fault Address Register (HPFAR/HDFAR) */
 #define HPFAR_MASK	(~UL(0xf))
diff --git a/arch/arm64/include/asm/system_misc.h b/arch/arm64/include/asm/system_misc.h
index 90daf4a..8522fff 100644
--- a/arch/arm64/include/asm/system_misc.h
+++ b/arch/arm64/include/asm/system_misc.h
@@ -77,4 +77,6 @@ extern void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
 int sea_register_handler_chain(struct notifier_block *nb);
 void sea_unregister_handler_chain(struct notifier_block *nb);
 
+int handle_guest_sea(unsigned long addr, unsigned int esr);
+
 #endif	/* __ASM_SYSTEM_MISC_H */
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 81cb7ad..d714432 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -597,6 +597,19 @@ static const char *fault_name(unsigned int esr)
 }
 
 /*
+ * Handle Synchronous External Aborts that occur in a guest kernel.
+ */
+int handle_guest_sea(unsigned long addr, unsigned int esr)
+{
+	atomic_notifier_call_chain(&sea_handler_chain, 0, NULL);
+
+	pr_err("Synchronous External Abort: %s (0x%08x) at 0x%016lx\n",
+		fault_name(esr), esr, addr);
+
+	return 0;
+}
+
+/*
  * Dispatch a data abort to the relevant handler.
  */
 asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr,
-- 
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