KVM: PPC: Handle some PAPR hcalls in the kernel
This adds the infrastructure for handling PAPR hcalls in the kernel,
either early in the guest exit path while we are still in real mode,
or later once the MMU has been turned back on and we are in the full
kernel context. The advantage of handling hcalls in real mode if
possible is that we avoid two partition switches -- and this will
become more important when we support SMT4 guests, since a partition
switch means we have to pull all of the threads in the core out of
the guest. The disadvantage is that we can only access the kernel
linear mapping, not anything vmalloced or ioremapped, since the MMU
is off.
This also adds code to handle the following hcalls in real mode:
H_ENTER Add an HPTE to the hashed page table
H_REMOVE Remove an HPTE from the hashed page table
H_READ Read HPTEs from the hashed page table
H_PROTECT Change the protection bits in an HPTE
H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table
H_SET_DABR Set the data address breakpoint register
Plus code to handle the following hcalls in the kernel:
H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives
H_PROD Wake up a ceded vcpu
H_REGISTER_VPA Register a virtual processor area (VPA)
The code that runs in real mode has to be in the base kernel, not in
the module, if KVM is compiled as a module. The real-mode code can
only access the kernel linear mapping, not vmalloc or ioremap space.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 9af2648..319ff63b 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -166,6 +166,14 @@
/* Save R1 in the PACA */
std r1, HSTATE_HOST_R1(r13)
+ /* Increment yield count if they have a VPA */
+ ld r3, VCPU_VPA(r4)
+ cmpdi r3, 0
+ beq 25f
+ lwz r5, LPPACA_YIELDCOUNT(r3)
+ addi r5, r5, 1
+ stw r5, LPPACA_YIELDCOUNT(r3)
+25:
/* Load up DAR and DSISR */
ld r5, VCPU_DAR(r4)
lwz r6, VCPU_DSISR(r4)
@@ -401,6 +409,10 @@
cmpwi r3,0
bge ignore_hdec
2:
+ /* See if this is something we can handle in real mode */
+ cmpwi r12,BOOK3S_INTERRUPT_SYSCALL
+ beq hcall_try_real_mode
+hcall_real_cont:
/* Check for mediated interrupts (could be done earlier really ...) */
cmpwi r12,BOOK3S_INTERRUPT_EXTERNAL
@@ -579,13 +591,28 @@
std r5, VCPU_SPRG2(r9)
std r6, VCPU_SPRG3(r9)
- /* Save PMU registers */
+ /* Increment yield count if they have a VPA */
+ ld r8, VCPU_VPA(r9) /* do they have a VPA? */
+ cmpdi r8, 0
+ beq 25f
+ lwz r3, LPPACA_YIELDCOUNT(r8)
+ addi r3, r3, 1
+ stw r3, LPPACA_YIELDCOUNT(r8)
+25:
+ /* Save PMU registers if requested */
+ /* r8 and cr0.eq are live here */
li r3, 1
sldi r3, r3, 31 /* MMCR0_FC (freeze counters) bit */
mfspr r4, SPRN_MMCR0 /* save MMCR0 */
mtspr SPRN_MMCR0, r3 /* freeze all counters, disable ints */
isync
- mfspr r5, SPRN_MMCR1
+ beq 21f /* if no VPA, save PMU stuff anyway */
+ lbz r7, LPPACA_PMCINUSE(r8)
+ cmpwi r7, 0 /* did they ask for PMU stuff to be saved? */
+ bne 21f
+ std r3, VCPU_MMCR(r9) /* if not, set saved MMCR0 to FC */
+ b 22f
+21: mfspr r5, SPRN_MMCR1
mfspr r6, SPRN_MMCRA
std r4, VCPU_MMCR(r9)
std r5, VCPU_MMCR + 8(r9)
@@ -676,6 +703,125 @@
mfspr r7,SPRN_HDSISR
b 7b
+/*
+ * Try to handle an hcall in real mode.
+ * Returns to the guest if we handle it, or continues on up to
+ * the kernel if we can't (i.e. if we don't have a handler for
+ * it, or if the handler returns H_TOO_HARD).
+ */
+ .globl hcall_try_real_mode
+hcall_try_real_mode:
+ ld r3,VCPU_GPR(r3)(r9)
+ andi. r0,r11,MSR_PR
+ bne hcall_real_cont
+ clrrdi r3,r3,2
+ cmpldi r3,hcall_real_table_end - hcall_real_table
+ bge hcall_real_cont
+ LOAD_REG_ADDR(r4, hcall_real_table)
+ lwzx r3,r3,r4
+ cmpwi r3,0
+ beq hcall_real_cont
+ add r3,r3,r4
+ mtctr r3
+ mr r3,r9 /* get vcpu pointer */
+ ld r4,VCPU_GPR(r4)(r9)
+ bctrl
+ cmpdi r3,H_TOO_HARD
+ beq hcall_real_fallback
+ ld r4,HSTATE_KVM_VCPU(r13)
+ std r3,VCPU_GPR(r3)(r4)
+ ld r10,VCPU_PC(r4)
+ ld r11,VCPU_MSR(r4)
+ b fast_guest_return
+
+ /* We've attempted a real mode hcall, but it's punted it back
+ * to userspace. We need to restore some clobbered volatiles
+ * before resuming the pass-it-to-qemu path */
+hcall_real_fallback:
+ li r12,BOOK3S_INTERRUPT_SYSCALL
+ ld r9, HSTATE_KVM_VCPU(r13)
+ ld r11, VCPU_MSR(r9)
+
+ b hcall_real_cont
+
+ .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 0 /* 0x10 - H_CLEAR_MOD */
+ .long 0 /* 0x14 - H_CLEAR_REF */
+ .long .kvmppc_h_protect - hcall_real_table
+ .long 0 /* 0x1c - H_GET_TCE */
+ .long 0 /* 0x20 - H_SET_TCE */
+ .long 0 /* 0x24 - H_SET_SPRG0 */
+ .long .kvmppc_h_set_dabr - hcall_real_table
+ .long 0 /* 0x2c */
+ .long 0 /* 0x30 */
+ .long 0 /* 0x34 */
+ .long 0 /* 0x38 */
+ .long 0 /* 0x3c */
+ .long 0 /* 0x40 */
+ .long 0 /* 0x44 */
+ .long 0 /* 0x48 */
+ .long 0 /* 0x4c */
+ .long 0 /* 0x50 */
+ .long 0 /* 0x54 */
+ .long 0 /* 0x58 */
+ .long 0 /* 0x5c */
+ .long 0 /* 0x60 */
+ .long 0 /* 0x64 */
+ .long 0 /* 0x68 */
+ .long 0 /* 0x6c */
+ .long 0 /* 0x70 */
+ .long 0 /* 0x74 */
+ .long 0 /* 0x78 */
+ .long 0 /* 0x7c */
+ .long 0 /* 0x80 */
+ .long 0 /* 0x84 */
+ .long 0 /* 0x88 */
+ .long 0 /* 0x8c */
+ .long 0 /* 0x90 */
+ .long 0 /* 0x94 */
+ .long 0 /* 0x98 */
+ .long 0 /* 0x9c */
+ .long 0 /* 0xa0 */
+ .long 0 /* 0xa4 */
+ .long 0 /* 0xa8 */
+ .long 0 /* 0xac */
+ .long 0 /* 0xb0 */
+ .long 0 /* 0xb4 */
+ .long 0 /* 0xb8 */
+ .long 0 /* 0xbc */
+ .long 0 /* 0xc0 */
+ .long 0 /* 0xc4 */
+ .long 0 /* 0xc8 */
+ .long 0 /* 0xcc */
+ .long 0 /* 0xd0 */
+ .long 0 /* 0xd4 */
+ .long 0 /* 0xd8 */
+ .long 0 /* 0xdc */
+ .long 0 /* 0xe0 */
+ .long 0 /* 0xe4 */
+ .long 0 /* 0xe8 */
+ .long 0 /* 0xec */
+ .long 0 /* 0xf0 */
+ .long 0 /* 0xf4 */
+ .long 0 /* 0xf8 */
+ .long 0 /* 0xfc */
+ .long 0 /* 0x100 */
+ .long 0 /* 0x104 */
+ .long 0 /* 0x108 */
+ .long 0 /* 0x10c */
+ .long 0 /* 0x110 */
+ .long 0 /* 0x114 */
+ .long 0 /* 0x118 */
+ .long 0 /* 0x11c */
+ .long 0 /* 0x120 */
+ .long .kvmppc_h_bulk_remove - hcall_real_table
+hcall_real_table_end:
+
ignore_hdec:
mr r4,r9
b fast_guest_return
@@ -688,10 +834,16 @@
LOAD_REG_IMMEDIATE(r11,MSR_SF | MSR_ME);
b fast_guest_return
+_GLOBAL(kvmppc_h_set_dabr)
+ std r4,VCPU_DABR(r3)
+ mtspr SPRN_DABR,r4
+ li r3,0
+ blr
+
/*
* Save away FP, VMX and VSX registers.
* r3 = vcpu pointer
-*/
+ */
_GLOBAL(kvmppc_save_fp)
mfmsr r9
ori r8,r9,MSR_FP