Merge tag 'nmiforkvm' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kernelorgnext
s390,kvm: provide plumbing for machines checks when running guests
This provides the basic plumbing for handling machine checks when
running guests
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 72bad67..41142d7 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -109,6 +109,20 @@ struct esca_block {
struct esca_entry cpu[KVM_S390_ESCA_CPU_SLOTS];
};
+/*
+ * This struct is used to store some machine check info from lowcore
+ * for machine checks that happen while the guest is running.
+ * This info in host's lowcore might be overwritten by a second machine
+ * check from host when host is in the machine check's high-level handling.
+ * The size is 24 bytes.
+ */
+struct mcck_volatile_info {
+ __u64 mcic;
+ __u64 failing_storage_address;
+ __u32 ext_damage_code;
+ __u32 reserved;
+};
+
#define CPUSTAT_STOPPED 0x80000000
#define CPUSTAT_WAIT 0x10000000
#define CPUSTAT_ECALL_PEND 0x08000000
@@ -266,7 +280,8 @@ struct kvm_s390_itdb {
struct sie_page {
struct kvm_s390_sie_block sie_block;
- __u8 reserved200[1024]; /* 0x0200 */
+ struct mcck_volatile_info mcck_info; /* 0x0200 */
+ __u8 reserved218[1000]; /* 0x0218 */
struct kvm_s390_itdb itdb; /* 0x0600 */
__u8 reserved700[2304]; /* 0x0700 */
};
diff --git a/arch/s390/include/asm/nmi.h b/arch/s390/include/asm/nmi.h
index e3e8895..13623b9 100644
--- a/arch/s390/include/asm/nmi.h
+++ b/arch/s390/include/asm/nmi.h
@@ -14,7 +14,14 @@
#include <linux/const.h>
#include <linux/types.h>
+#define MCIC_SUBCLASS_MASK (1ULL<<63 | 1ULL<<62 | 1ULL<<61 | \
+ 1ULL<<59 | 1ULL<<58 | 1ULL<<56 | \
+ 1ULL<<55 | 1ULL<<54 | 1ULL<<53 | \
+ 1ULL<<52 | 1ULL<<47 | 1ULL<<46 | \
+ 1ULL<<45 | 1ULL<<44)
#define MCCK_CODE_SYSTEM_DAMAGE _BITUL(63)
+#define MCCK_CODE_EXT_DAMAGE _BITUL(63 - 5)
+#define MCCK_CODE_CP _BITUL(63 - 9)
#define MCCK_CODE_CPU_TIMER_VALID _BITUL(63 - 46)
#define MCCK_CODE_PSW_MWP_VALID _BITUL(63 - 20)
#define MCCK_CODE_PSW_IA_VALID _BITUL(63 - 23)
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 60d395f..5b1b247 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -20,6 +20,7 @@
#define CIF_FPU 4 /* restore FPU registers */
#define CIF_IGNORE_IRQ 5 /* ignore interrupt (for udelay) */
#define CIF_ENABLED_WAIT 6 /* in enabled wait state */
+#define CIF_MCCK_GUEST 7 /* machine check happening in guest */
#define _CIF_MCCK_PENDING _BITUL(CIF_MCCK_PENDING)
#define _CIF_ASCE_PRIMARY _BITUL(CIF_ASCE_PRIMARY)
@@ -28,6 +29,7 @@
#define _CIF_FPU _BITUL(CIF_FPU)
#define _CIF_IGNORE_IRQ _BITUL(CIF_IGNORE_IRQ)
#define _CIF_ENABLED_WAIT _BITUL(CIF_ENABLED_WAIT)
+#define _CIF_MCCK_GUEST _BITUL(CIF_MCCK_GUEST)
#ifndef __ASSEMBLY__
diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
index 6bb2963..b65c414 100644
--- a/arch/s390/kernel/asm-offsets.c
+++ b/arch/s390/kernel/asm-offsets.c
@@ -58,6 +58,9 @@ int main(void)
OFFSET(__SF_BACKCHAIN, stack_frame, back_chain);
OFFSET(__SF_GPRS, stack_frame, gprs);
OFFSET(__SF_EMPTY, stack_frame, empty1);
+ OFFSET(__SF_SIE_CONTROL, stack_frame, empty1[0]);
+ OFFSET(__SF_SIE_SAVEAREA, stack_frame, empty1[1]);
+ OFFSET(__SF_SIE_REASON, stack_frame, empty1[2]);
BLANK();
/* timeval/timezone offsets for use by vdso */
OFFSET(__VDSO_UPD_COUNT, vdso_data, tb_update_count);
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index e408d9c..3b4b158 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -225,6 +225,7 @@
jnz .Lsie_skip
TSTMSK __LC_CPU_FLAGS,_CIF_FPU
jo .Lsie_skip # exit if fp/vx regs changed
+.Lsie_entry:
sie 0(%r14)
.Lsie_skip:
ni __SIE_PROG0C+3(%r14),0xfe # no longer in SIE
@@ -1104,7 +1105,13 @@
.quad .Lsie_done
.Lcleanup_sie:
- lg %r9,__SF_EMPTY(%r15) # get control block pointer
+ cghi %r11,__LC_SAVE_AREA_ASYNC #Is this in normal interrupt?
+ je 1f
+ slg %r9,BASED(.Lsie_crit_mcck_start)
+ clg %r9,BASED(.Lsie_crit_mcck_length)
+ jh 1f
+ oi __LC_CPU_FLAGS+7, _CIF_MCCK_GUEST
+1: lg %r9,__SF_EMPTY(%r15) # get control block pointer
ni __SIE_PROG0C+3(%r9),0xfe # no longer in SIE
lctlg %c1,%c1,__LC_USER_ASCE # load primary asce
larl %r9,sie_exit # skip forward to sie_exit
@@ -1289,6 +1296,10 @@
.quad .Lsie_gmap
.Lsie_critical_length:
.quad .Lsie_done - .Lsie_gmap
+.Lsie_crit_mcck_start:
+ .quad .Lsie_entry
+.Lsie_crit_mcck_length:
+ .quad .Lsie_skip - .Lsie_entry
#endif
.section .rodata, "a"
diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
index 9855895..31d03a8 100644
--- a/arch/s390/kernel/nmi.c
+++ b/arch/s390/kernel/nmi.c
@@ -25,6 +25,8 @@
#include <asm/crw.h>
#include <asm/switch_to.h>
#include <asm/ctl_reg.h>
+#include <asm/asm-offsets.h>
+#include <linux/kvm_host.h>
struct mcck_struct {
unsigned int kill_task : 1;
@@ -274,12 +276,39 @@ static int notrace s390_validate_registers(union mci mci, int umode)
return kill_task;
}
+/*
+ * Backup the guest's machine check info to its description block
+ */
+static void notrace s390_backup_mcck_info(struct pt_regs *regs)
+{
+ struct mcck_volatile_info *mcck_backup;
+ struct sie_page *sie_page;
+
+ /* r14 contains the sie block, which was set in sie64a */
+ struct kvm_s390_sie_block *sie_block =
+ (struct kvm_s390_sie_block *) regs->gprs[14];
+
+ if (sie_block == NULL)
+ /* Something's seriously wrong, stop system. */
+ s390_handle_damage();
+
+ sie_page = container_of(sie_block, struct sie_page, sie_block);
+ mcck_backup = &sie_page->mcck_info;
+ mcck_backup->mcic = S390_lowcore.mcck_interruption_code &
+ ~(MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE);
+ mcck_backup->ext_damage_code = S390_lowcore.external_damage_code;
+ mcck_backup->failing_storage_address
+ = S390_lowcore.failing_storage_address;
+}
+
#define MAX_IPD_COUNT 29
#define MAX_IPD_TIME (5 * 60 * USEC_PER_SEC) /* 5 minutes */
#define ED_STP_ISLAND 6 /* External damage STP island check */
#define ED_STP_SYNC 7 /* External damage STP sync check */
+#define MCCK_CODE_NO_GUEST (MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE)
+
/*
* machine check handler.
*/
@@ -291,6 +320,7 @@ void notrace s390_do_machine_check(struct pt_regs *regs)
struct mcck_struct *mcck;
unsigned long long tmp;
union mci mci;
+ unsigned long mcck_dam_code;
nmi_enter();
inc_irq_stat(NMI_NMI);
@@ -301,7 +331,13 @@ void notrace s390_do_machine_check(struct pt_regs *regs)
/* System damage -> stopping machine */
s390_handle_damage();
}
- if (mci.pd) {
+
+ /*
+ * Reinject the instruction processing damages' machine checks
+ * including Delayed Access Exception into the guest
+ * instead of damaging the host if they happen in the guest.
+ */
+ if (mci.pd && !test_cpu_flag(CIF_MCCK_GUEST)) {
if (mci.b) {
/* Processing backup -> verify if we can survive this */
u64 z_mcic, o_mcic, t_mcic;
@@ -345,6 +381,14 @@ void notrace s390_do_machine_check(struct pt_regs *regs)
mcck->mcck_code = mci.val;
set_cpu_flag(CIF_MCCK_PENDING);
}
+
+ /*
+ * Backup the machine check's info if it happens when the guest
+ * is running.
+ */
+ if (test_cpu_flag(CIF_MCCK_GUEST))
+ s390_backup_mcck_info(regs);
+
if (mci.cd) {
/* Timing facility damage */
s390_handle_damage();
@@ -358,15 +402,22 @@ void notrace s390_do_machine_check(struct pt_regs *regs)
if (mcck->stp_queue)
set_cpu_flag(CIF_MCCK_PENDING);
}
- if (mci.se)
- /* Storage error uncorrected */
- s390_handle_damage();
- if (mci.ke)
- /* Storage key-error uncorrected */
- s390_handle_damage();
- if (mci.ds && mci.fa)
- /* Storage degradation */
- s390_handle_damage();
+
+ /*
+ * Reinject storage related machine checks into the guest if they
+ * happen when the guest is running.
+ */
+ if (!test_cpu_flag(CIF_MCCK_GUEST)) {
+ if (mci.se)
+ /* Storage error uncorrected */
+ s390_handle_damage();
+ if (mci.ke)
+ /* Storage key-error uncorrected */
+ s390_handle_damage();
+ if (mci.ds && mci.fa)
+ /* Storage degradation */
+ s390_handle_damage();
+ }
if (mci.cp) {
/* Channel report word pending */
mcck->channel_report = 1;
@@ -377,6 +428,19 @@ void notrace s390_do_machine_check(struct pt_regs *regs)
mcck->warning = 1;
set_cpu_flag(CIF_MCCK_PENDING);
}
+
+ /*
+ * If there are only Channel Report Pending and External Damage
+ * machine checks, they will not be reinjected into the guest
+ * because they refer to host conditions only.
+ */
+ mcck_dam_code = (mci.val & MCIC_SUBCLASS_MASK);
+ if (test_cpu_flag(CIF_MCCK_GUEST) &&
+ (mcck_dam_code & MCCK_CODE_NO_GUEST) != mcck_dam_code) {
+ /* Set exit reason code for host's later handling */
+ *((long *)(regs->gprs[15] + __SF_SIE_REASON)) = -EINTR;
+ }
+ clear_cpu_flag(CIF_MCCK_GUEST);
nmi_exit();
}
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index e100a7f..90434760 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2405,6 +2405,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
if (!vcpu)
goto out;
+ BUILD_BUG_ON(sizeof(struct sie_page) != 4096);
sie_page = (struct sie_page *) get_zeroed_page(GFP_KERNEL);
if (!sie_page)
goto out_free_cpu;