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KVM: PPC: Use PACA backed shadow vcpu
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We're being horribly racy right now. All the entry and exit code hijacks
random fields from the PACA that could easily be used by different code in
case we get interrupted, for example by a #MC or even page fault.

After discussing this with Ben, we figured it's best to reserve some more
space in the PACA and just shove off some vcpu state to there.

That way we can drastically improve the readability of the code, make it
less racy and less complex.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Alexander Graf authored and Marcelo Tosatti committed Mar 1, 2010
1 parent 992b5b2 commit 7e57cba
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Showing 10 changed files with 249 additions and 237 deletions.
2 changes: 2 additions & 0 deletions arch/powerpc/include/asm/kvm_book3s.h
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Expand Up @@ -23,6 +23,7 @@
#include <linux/types.h>
#include <linux/kvm_host.h>
#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s_64_asm.h>

struct kvmppc_slb {
u64 esid;
Expand Down Expand Up @@ -69,6 +70,7 @@ struct kvmppc_sid_map {

struct kvmppc_vcpu_book3s {
struct kvm_vcpu vcpu;
struct kvmppc_book3s_shadow_vcpu shadow_vcpu;
struct kvmppc_sid_map sid_map[SID_MAP_NUM];
struct kvmppc_slb slb[64];
struct {
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19 changes: 19 additions & 0 deletions arch/powerpc/include/asm/kvm_book3s_64_asm.h
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Expand Up @@ -20,6 +20,8 @@
#ifndef __ASM_KVM_BOOK3S_ASM_H__
#define __ASM_KVM_BOOK3S_ASM_H__

#ifdef __ASSEMBLY__

#ifdef CONFIG_KVM_BOOK3S_64_HANDLER

#include <asm/kvm_asm.h>
Expand Down Expand Up @@ -55,4 +57,21 @@ kvmppc_resume_\intno:

#endif /* CONFIG_KVM_BOOK3S_64_HANDLER */

#else /*__ASSEMBLY__ */

struct kvmppc_book3s_shadow_vcpu {
ulong gpr[14];
u32 cr;
u32 xer;
ulong host_r1;
ulong host_r2;
ulong handler;
ulong scratch0;
ulong scratch1;
ulong vmhandler;
ulong rmhandler;
};

#endif /*__ASSEMBLY__ */

#endif /* __ASM_KVM_BOOK3S_ASM_H__ */
5 changes: 4 additions & 1 deletion arch/powerpc/include/asm/kvm_host.h
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Expand Up @@ -175,10 +175,13 @@ struct kvm_vcpu_arch {
ulong gpr[32];

ulong pc;
u32 cr;
ulong ctr;
ulong lr;

#ifdef CONFIG_BOOKE
ulong xer;
u32 cr;
#endif

ulong msr;
#ifdef CONFIG_PPC64
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20 changes: 14 additions & 6 deletions arch/powerpc/include/asm/kvm_ppc.h
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Expand Up @@ -98,34 +98,42 @@ extern void kvmppc_core_destroy_mmu(struct kvm_vcpu *vcpu);

#ifdef CONFIG_PPC_BOOK3S

/* We assume we're always acting on the current vcpu */

static inline void kvmppc_set_gpr(struct kvm_vcpu *vcpu, int num, ulong val)
{
vcpu->arch.gpr[num] = val;
if ( num < 14 )
get_paca()->shadow_vcpu.gpr[num] = val;
else
vcpu->arch.gpr[num] = val;
}

static inline ulong kvmppc_get_gpr(struct kvm_vcpu *vcpu, int num)
{
return vcpu->arch.gpr[num];
if ( num < 14 )
return get_paca()->shadow_vcpu.gpr[num];
else
return vcpu->arch.gpr[num];
}

static inline void kvmppc_set_cr(struct kvm_vcpu *vcpu, u32 val)
{
vcpu->arch.cr = val;
get_paca()->shadow_vcpu.cr = val;
}

static inline u32 kvmppc_get_cr(struct kvm_vcpu *vcpu)
{
return vcpu->arch.cr;
return get_paca()->shadow_vcpu.cr;
}

static inline void kvmppc_set_xer(struct kvm_vcpu *vcpu, u32 val)
{
vcpu->arch.xer = val;
get_paca()->shadow_vcpu.xer = val;
}

static inline u32 kvmppc_get_xer(struct kvm_vcpu *vcpu)
{
return vcpu->arch.xer;
return get_paca()->shadow_vcpu.xer;
}

#else
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5 changes: 5 additions & 0 deletions arch/powerpc/include/asm/paca.h
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Expand Up @@ -19,6 +19,9 @@
#include <asm/mmu.h>
#include <asm/page.h>
#include <asm/exception-64e.h>
#ifdef CONFIG_KVM_BOOK3S_64_HANDLER
#include <asm/kvm_book3s_64_asm.h>
#endif

register struct paca_struct *local_paca asm("r13");

Expand Down Expand Up @@ -135,6 +138,8 @@ struct paca_struct {
u64 esid;
u64 vsid;
} kvm_slb[64]; /* guest SLB */
/* We use this to store guest state in */
struct kvmppc_book3s_shadow_vcpu shadow_vcpu;
u8 kvm_slb_max; /* highest used guest slb entry */
u8 kvm_in_guest; /* are we inside the guest? */
#endif
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33 changes: 30 additions & 3 deletions arch/powerpc/kernel/asm-offsets.c
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Expand Up @@ -194,6 +194,32 @@ int main(void)
DEFINE(PACA_KVM_IN_GUEST, offsetof(struct paca_struct, kvm_in_guest));
DEFINE(PACA_KVM_SLB, offsetof(struct paca_struct, kvm_slb));
DEFINE(PACA_KVM_SLB_MAX, offsetof(struct paca_struct, kvm_slb_max));
DEFINE(PACA_KVM_CR, offsetof(struct paca_struct, shadow_vcpu.cr));
DEFINE(PACA_KVM_XER, offsetof(struct paca_struct, shadow_vcpu.xer));
DEFINE(PACA_KVM_R0, offsetof(struct paca_struct, shadow_vcpu.gpr[0]));
DEFINE(PACA_KVM_R1, offsetof(struct paca_struct, shadow_vcpu.gpr[1]));
DEFINE(PACA_KVM_R2, offsetof(struct paca_struct, shadow_vcpu.gpr[2]));
DEFINE(PACA_KVM_R3, offsetof(struct paca_struct, shadow_vcpu.gpr[3]));
DEFINE(PACA_KVM_R4, offsetof(struct paca_struct, shadow_vcpu.gpr[4]));
DEFINE(PACA_KVM_R5, offsetof(struct paca_struct, shadow_vcpu.gpr[5]));
DEFINE(PACA_KVM_R6, offsetof(struct paca_struct, shadow_vcpu.gpr[6]));
DEFINE(PACA_KVM_R7, offsetof(struct paca_struct, shadow_vcpu.gpr[7]));
DEFINE(PACA_KVM_R8, offsetof(struct paca_struct, shadow_vcpu.gpr[8]));
DEFINE(PACA_KVM_R9, offsetof(struct paca_struct, shadow_vcpu.gpr[9]));
DEFINE(PACA_KVM_R10, offsetof(struct paca_struct, shadow_vcpu.gpr[10]));
DEFINE(PACA_KVM_R11, offsetof(struct paca_struct, shadow_vcpu.gpr[11]));
DEFINE(PACA_KVM_R12, offsetof(struct paca_struct, shadow_vcpu.gpr[12]));
DEFINE(PACA_KVM_R13, offsetof(struct paca_struct, shadow_vcpu.gpr[13]));
DEFINE(PACA_KVM_HOST_R1, offsetof(struct paca_struct, shadow_vcpu.host_r1));
DEFINE(PACA_KVM_HOST_R2, offsetof(struct paca_struct, shadow_vcpu.host_r2));
DEFINE(PACA_KVM_VMHANDLER, offsetof(struct paca_struct,
shadow_vcpu.vmhandler));
DEFINE(PACA_KVM_RMHANDLER, offsetof(struct paca_struct,
shadow_vcpu.rmhandler));
DEFINE(PACA_KVM_SCRATCH0, offsetof(struct paca_struct,
shadow_vcpu.scratch0));
DEFINE(PACA_KVM_SCRATCH1, offsetof(struct paca_struct,
shadow_vcpu.scratch1));
#endif
#endif /* CONFIG_PPC64 */

Expand Down Expand Up @@ -389,8 +415,6 @@ int main(void)
DEFINE(VCPU_HOST_PID, offsetof(struct kvm_vcpu, arch.host_pid));
DEFINE(VCPU_GPRS, offsetof(struct kvm_vcpu, arch.gpr));
DEFINE(VCPU_LR, offsetof(struct kvm_vcpu, arch.lr));
DEFINE(VCPU_CR, offsetof(struct kvm_vcpu, arch.cr));
DEFINE(VCPU_XER, offsetof(struct kvm_vcpu, arch.xer));
DEFINE(VCPU_CTR, offsetof(struct kvm_vcpu, arch.ctr));
DEFINE(VCPU_PC, offsetof(struct kvm_vcpu, arch.pc));
DEFINE(VCPU_MSR, offsetof(struct kvm_vcpu, arch.msr));
Expand All @@ -415,7 +439,10 @@ int main(void)
DEFINE(VCPU_TRAMPOLINE_ENTER, offsetof(struct kvm_vcpu, arch.trampoline_enter));
DEFINE(VCPU_HIGHMEM_HANDLER, offsetof(struct kvm_vcpu, arch.highmem_handler));
DEFINE(VCPU_HFLAGS, offsetof(struct kvm_vcpu, arch.hflags));
#endif
#else
DEFINE(VCPU_CR, offsetof(struct kvm_vcpu, arch.cr));
DEFINE(VCPU_XER, offsetof(struct kvm_vcpu, arch.xer));
#endif /* CONFIG_PPC64 */
#endif
#ifdef CONFIG_44x
DEFINE(PGD_T_LOG2, PGD_T_LOG2);
Expand Down
4 changes: 4 additions & 0 deletions arch/powerpc/kvm/book3s.c
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Original file line number Diff line number Diff line change
Expand Up @@ -66,12 +66,16 @@ void kvmppc_core_load_guest_debugstate(struct kvm_vcpu *vcpu)
void kvmppc_core_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
memcpy(get_paca()->kvm_slb, to_book3s(vcpu)->slb_shadow, sizeof(get_paca()->kvm_slb));
memcpy(&get_paca()->shadow_vcpu, &to_book3s(vcpu)->shadow_vcpu,
sizeof(get_paca()->shadow_vcpu));
get_paca()->kvm_slb_max = to_book3s(vcpu)->slb_shadow_max;
}

void kvmppc_core_vcpu_put(struct kvm_vcpu *vcpu)
{
memcpy(to_book3s(vcpu)->slb_shadow, get_paca()->kvm_slb, sizeof(get_paca()->kvm_slb));
memcpy(&to_book3s(vcpu)->shadow_vcpu, &get_paca()->shadow_vcpu,
sizeof(get_paca()->shadow_vcpu));
to_book3s(vcpu)->slb_shadow_max = get_paca()->kvm_slb_max;
}

Expand Down
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