powerpc/book3s: Fix guest MC delivery mechanism to avoid soft lockups in guest.

[mirror_ubuntu-artful-kernel.git] / arch / powerpc / kvm / book3s_hv_rmhandlers.S

diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 974793435a2e20e82a22780b3e7ad330c17ccf40..868347ef09fd48bcf8bfd343becb49f6898887c5 100644 (file)
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -292,8 +292,7 @@ kvm_start_guest:
        beq     kvm_no_guest
 
        /* Set HSTATE_DSCR(r13) to something sensible */
-       LOAD_REG_ADDR(r6, dscr_default)
-       ld      r6, 0(r6)
+       ld      r6, PACA_DSCR(r13)
        std     r6, HSTATE_DSCR(r13)
 
        bl      kvmppc_hv_entry
@@ -1799,7 +1798,7 @@ kvmppc_hdsi:
        /* Search the hash table. */
        mr      r3, r9                  /* vcpu pointer */
        li      r7, 1                   /* data fault */
-       bl      .kvmppc_hpte_hv_fault
+       bl      kvmppc_hpte_hv_fault
        ld      r9, HSTATE_KVM_VCPU(r13)
        ld      r10, VCPU_PC(r9)
        ld      r11, VCPU_MSR(r9)
@@ -1873,7 +1872,7 @@ kvmppc_hisi:
        mr      r4, r10
        mr      r6, r11
        li      r7, 0                   /* instruction fault */
-       bl      .kvmppc_hpte_hv_fault
+       bl      kvmppc_hpte_hv_fault
        ld      r9, HSTATE_KVM_VCPU(r13)
        ld      r10, VCPU_PC(r9)
        ld      r11, VCPU_MSR(r9)
@@ -1947,16 +1946,16 @@ hcall_real_fallback:
        .globl  hcall_real_table
 hcall_real_table:
        .long   0               /* 0 - unused */
-       .long   .kvmppc_h_remove - hcall_real_table
-       .long   .kvmppc_h_enter - hcall_real_table
-       .long   .kvmppc_h_read - hcall_real_table
+       .long   DOTSYM(kvmppc_h_remove) - hcall_real_table
+       .long   DOTSYM(kvmppc_h_enter) - hcall_real_table
+       .long   DOTSYM(kvmppc_h_read) - hcall_real_table
        .long   0               /* 0x10 - H_CLEAR_MOD */
        .long   0               /* 0x14 - H_CLEAR_REF */
-       .long   .kvmppc_h_protect - hcall_real_table
-       .long   .kvmppc_h_get_tce - hcall_real_table
-       .long   .kvmppc_h_put_tce - hcall_real_table
+       .long   DOTSYM(kvmppc_h_protect) - hcall_real_table
+       .long   DOTSYM(kvmppc_h_get_tce) - hcall_real_table
+       .long   DOTSYM(kvmppc_h_put_tce) - hcall_real_table
        .long   0               /* 0x24 - H_SET_SPRG0 */
-       .long   .kvmppc_h_set_dabr - hcall_real_table
+       .long   DOTSYM(kvmppc_h_set_dabr) - hcall_real_table
        .long   0               /* 0x2c */
        .long   0               /* 0x30 */
        .long   0               /* 0x34 */
@@ -1972,11 +1971,11 @@ hcall_real_table:
        .long   0               /* 0x5c */
        .long   0               /* 0x60 */
 #ifdef CONFIG_KVM_XICS
-       .long   .kvmppc_rm_h_eoi - hcall_real_table
-       .long   .kvmppc_rm_h_cppr - hcall_real_table
-       .long   .kvmppc_rm_h_ipi - hcall_real_table
+       .long   DOTSYM(kvmppc_rm_h_eoi) - hcall_real_table
+       .long   DOTSYM(kvmppc_rm_h_cppr) - hcall_real_table
+       .long   DOTSYM(kvmppc_rm_h_ipi) - hcall_real_table
        .long   0               /* 0x70 - H_IPOLL */
-       .long   .kvmppc_rm_h_xirr - hcall_real_table
+       .long   DOTSYM(kvmppc_rm_h_xirr) - hcall_real_table
 #else
        .long   0               /* 0x64 - H_EOI */
        .long   0               /* 0x68 - H_CPPR */
@@ -2010,7 +2009,7 @@ hcall_real_table:
        .long   0               /* 0xd4 */
        .long   0               /* 0xd8 */
        .long   0               /* 0xdc */
-       .long   .kvmppc_h_cede - hcall_real_table
+       .long   DOTSYM(kvmppc_h_cede) - hcall_real_table
        .long   0               /* 0xe4 */
        .long   0               /* 0xe8 */
        .long   0               /* 0xec */
@@ -2027,11 +2026,11 @@ hcall_real_table:
        .long   0               /* 0x118 */
        .long   0               /* 0x11c */
        .long   0               /* 0x120 */
-       .long   .kvmppc_h_bulk_remove - hcall_real_table
+       .long   DOTSYM(kvmppc_h_bulk_remove) - hcall_real_table
        .long   0               /* 0x128 */
        .long   0               /* 0x12c */
        .long   0               /* 0x130 */
-       .long   .kvmppc_h_set_xdabr - hcall_real_table
+       .long   DOTSYM(kvmppc_h_set_xdabr) - hcall_real_table
 hcall_real_table_end:
 
 ignore_hdec:
@@ -2256,17 +2255,30 @@ kvm_cede_exit:
        /* Try to handle a machine check in real mode */
 machine_check_realmode:
        mr      r3, r9          /* get vcpu pointer */
-       bl      .kvmppc_realmode_machine_check
+       bl      kvmppc_realmode_machine_check
        nop
-       cmpdi   r3, 0           /* continue exiting from guest? */
+       cmpdi   r3, 0           /* Did we handle MCE ? */
        ld      r9, HSTATE_KVM_VCPU(r13)
        li      r12, BOOK3S_INTERRUPT_MACHINE_CHECK
-       beq     mc_cont
+       /*
+        * Deliver unhandled/fatal (e.g. UE) MCE errors to guest through
+        * machine check interrupt (set HSRR0 to 0x200). And for handled
+        * errors (no-fatal), just go back to guest execution with current
+        * HSRR0 instead of exiting guest. This new approach will inject
+        * machine check to guest for fatal error causing guest to crash.
+        *
+        * The old code used to return to host for unhandled errors which
+        * was causing guest to hang with soft lockups inside guest and
+        * makes it difficult to recover guest instance.
+        */
+       ld      r10, VCPU_PC(r9)
+       ld      r11, VCPU_MSR(r9)
+       bne     2f      /* Continue guest execution. */
        /* If not, deliver a machine check.  SRR0/1 are already set */
        li      r10, BOOK3S_INTERRUPT_MACHINE_CHECK
        ld      r11, VCPU_MSR(r9)
        bl      kvmppc_msr_interrupt
-       b       fast_interrupt_c_return
+2:     b       fast_interrupt_c_return
 
 /*
  * Check the reason we woke from nap, and take appropriate action.