arm/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.

When an SEA occurs in the guest kernel, the guest exits and is
routed to kvm_handle_guest_abort(). Prior to this patch, a print
message of an unsupported FSC would be printed and nothing else
would happen. With this patch, the code gets routed to the APEI
handling of SEAs in the host kernel to report the SEA information.

BugLink: https://launchpad.net/bugs/1696570
Signed-off-by: Tyler Baicar <tbaicar@codeaurora.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
(backported from commit 621f48e40ee9b0100a802531069166d7d94796e0)
Signed-off-by: Manoj Iyer <manoj.iyer@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

diff --git a/arch/arm/include/asm/kvm_arm.h b/arch/arm/include/asm/kvm_arm.h
index e22089fb44dc86b7ed2fdb175bc6ec7b47ee4001..a1a3dff2c83bb079211cbb3ea6afc565d5cee71b 100644 (file)
--- a/arch/arm/include/asm/kvm_arm.h
+++ b/arch/arm/include/asm/kvm_arm.h
@@ -187,6 +187,16 @@
 #define FSC_FAULT      (0x04)
 #define FSC_ACCESS     (0x08)
 #define FSC_PERM       (0x0c)
+#define FSC_SEA                (0x10)
+#define FSC_SEA_TTW0   (0x14)
+#define FSC_SEA_TTW1   (0x15)
+#define FSC_SEA_TTW2   (0x16)
+#define FSC_SEA_TTW3   (0x17)
+#define FSC_SECC       (0x18)
+#define FSC_SECC_TTW0  (0x1c)
+#define FSC_SECC_TTW1  (0x1d)
+#define FSC_SECC_TTW2  (0x1e)
+#define FSC_SECC_TTW3  (0x1f)
 
 /* 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 a3d61ad984af7e7a9fcd967530141477132f9bac..8c4a89f5ce7d5fe425f7918519930faccbf16224 100644 (file)
--- a/arch/arm/include/asm/system_misc.h
+++ b/arch/arm/include/asm/system_misc.h
@@ -22,6 +22,11 @@ extern void (*arm_pm_idle)(void);
 
 extern unsigned int user_debug;
 
+static inline int handle_guest_sea(phys_addr_t addr, unsigned int esr)
+{
+       return -1;
+}
+
 #endif /* !__ASSEMBLY__ */
 
 #endif /* __ASM_ARM_SYSTEM_MISC_H */

diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 2fd5c135e8a4c07959dc096d24cd1edfa8e20222..9ed6d8309f1411b6612ff8ae416ea948b11170a4 100644 (file)
--- 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"
 
@@ -1421,6 +1422,25 @@ out:
                kvm_set_pfn_accessed(pfn);
 }
 
+static bool is_abort_sea(unsigned long fault_status)
+{
+       switch (fault_status) {
+       case FSC_SEA:
+       case FSC_SEA_TTW0:
+       case FSC_SEA_TTW1:
+       case FSC_SEA_TTW2:
+       case FSC_SEA_TTW3:
+       case FSC_SECC:
+       case FSC_SECC_TTW0:
+       case FSC_SECC_TTW1:
+       case FSC_SECC_TTW2:
+       case FSC_SECC_TTW3:
+               return true;
+       default:
+               return false;
+       }
+}
+
 /**
  * kvm_handle_guest_abort - handles all 2nd stage aborts
  * @vcpu:      the VCPU pointer
@@ -1443,19 +1463,29 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run)
        gfn_t gfn;
        int ret, idx;
 
+       fault_status = kvm_vcpu_trap_get_fault_type(vcpu);
+
+       fault_ipa = kvm_vcpu_get_fault_ipa(vcpu);
+
+       /*
+        * The host kernel will handle the synchronous external abort. There
+        * is no need to pass the error into the guest.
+        */
+       if (is_abort_sea(fault_status)) {
+               if (!handle_guest_sea(fault_ipa, kvm_vcpu_get_hsr(vcpu)))
+                       return 1;
+       }
+
        is_iabt = kvm_vcpu_trap_is_iabt(vcpu);
        if (unlikely(!is_iabt && kvm_vcpu_dabt_isextabt(vcpu))) {
                kvm_inject_vabt(vcpu);
                return 1;
        }
 
-       fault_ipa = kvm_vcpu_get_fault_ipa(vcpu);
-
        trace_kvm_guest_fault(*vcpu_pc(vcpu), kvm_vcpu_get_hsr(vcpu),
                              kvm_vcpu_get_hfar(vcpu), fault_ipa);
 
        /* 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) {
                kvm_err("Unsupported FSC: EC=%#x xFSC=%#lx ESR_EL2=%#lx\n",

diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index 2a2752b5b6aa7a424c956d4dd0ec2642644762de..dcacdbb890a07d81d6e3f05fbe7d8263b7393edd 100644 (file)
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -201,6 +201,16 @@
 #define FSC_FAULT      ESR_ELx_FSC_FAULT
 #define FSC_ACCESS     ESR_ELx_FSC_ACCESS
 #define FSC_PERM       ESR_ELx_FSC_PERM
+#define FSC_SEA                ESR_ELx_FSC_EXTABT
+#define FSC_SEA_TTW0   (0x14)
+#define FSC_SEA_TTW1   (0x15)
+#define FSC_SEA_TTW2   (0x16)
+#define FSC_SEA_TTW3   (0x17)
+#define FSC_SECC       (0x18)
+#define FSC_SECC_TTW0  (0x1c)
+#define FSC_SECC_TTW1  (0x1d)
+#define FSC_SECC_TTW2  (0x1e)
+#define FSC_SECC_TTW3  (0x1f)
 
 /* 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 bc812435bc76278080851920744defcc1d78e270..95aa4423247d66237e688eb494426187f8afed5f 100644 (file)
--- a/arch/arm64/include/asm/system_misc.h
+++ b/arch/arm64/include/asm/system_misc.h
@@ -56,6 +56,8 @@ extern void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
        __show_ratelimited;                                             \
 })
 
+int handle_guest_sea(phys_addr_t addr, unsigned int esr);
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* __ASM_SYSTEM_MISC_H */

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 0a78bf9bf77d55bf53c0726e668c7a36a55ab2d4..d60f29e19809e1680b1cd046639f103bb263526a 100644 (file)
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -514,6 +514,7 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs)
 {
        struct siginfo info;
        const struct fault_info *inf;
+       int ret = 0;
 
        inf = esr_to_fault_info(esr);
        pr_err("Synchronous External Abort: %s (0x%08x) at 0x%016lx\n",
@@ -528,7 +529,7 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs)
                if (interrupts_enabled(regs))
                        nmi_enter();
 
-               ghes_notify_sea();
+               ret = ghes_notify_sea();
 
                if (interrupts_enabled(regs))
                        nmi_exit();
@@ -543,7 +544,7 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs)
                info.si_addr  = (void __user *)addr;
        arm64_notify_die("", regs, &info, esr);
 
-       return 0;
+       return ret;
 }
 
 static const struct fault_info fault_info[] = {
@@ -613,6 +614,23 @@ static const struct fault_info fault_info[] = {
        { do_bad,               SIGBUS,  0,             "unknown 63"                    },
 };
 
+/*
+ * Handle Synchronous External Aborts that occur in a guest kernel.
+ *
+ * The return value will be zero if the SEA was successfully handled
+ * and non-zero if there was an error processing the error or there was
+ * no error to process.
+ */
+int handle_guest_sea(phys_addr_t addr, unsigned int esr)
+{
+       int ret = -ENOENT;
+
+       if (IS_ENABLED(CONFIG_ACPI_APEI_SEA))
+               ret = ghes_notify_sea();
+
+       return ret;
+}
+
 /*
  * Dispatch a data abort to the relevant handler.
  */

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index bd54617a4fd3ff32f3d53eeeb301a50515fe8423..70ea44968ace2ed888c73ae2a5dae18fb806ab77 100644 (file)
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -818,17 +818,22 @@ static struct notifier_block ghes_notifier_sci = {
 #ifdef CONFIG_ACPI_APEI_SEA
 static LIST_HEAD(ghes_sea);
 
-void ghes_notify_sea(void)
+/*
+ * Return 0 only if one of the SEA error sources successfully reported an error
+ * record sent from the firmware.
+ */
+int ghes_notify_sea(void)
 {
        struct ghes *ghes;
+       int ret = -ENOENT;
 
-       /*
-        * synchronize_rcu() will wait for nmi_exit(), so no need to
-        * rcu_read_lock().
-        */
+       rcu_read_lock();
        list_for_each_entry_rcu(ghes, &ghes_sea, list) {
-               ghes_proc(ghes);
+               if (!ghes_proc(ghes))
+                       ret = 0;
        }
+       rcu_read_unlock();
+       return ret;
 }
 
 static void ghes_sea_add(struct ghes *ghes)

diff --git a/include/acpi/ghes.h b/include/acpi/ghes.h
index 95305aeb13ff79265dea8c33f3a12145722d8134..9f26e01186aea6ccd37d1c7771de3978d9111bb5 100644 (file)
--- a/include/acpi/ghes.h
+++ b/include/acpi/ghes.h
@@ -113,6 +113,6 @@ static inline void *acpi_hest_get_next(struct acpi_hest_generic_data *gdata)
        return (void *)(gdata) + acpi_hest_get_record_size(gdata);
 }
 
-void ghes_notify_sea(void);
+int ghes_notify_sea(void);
 
 #endif /* GHES_H */