Commit 4bad7779 authored by Paul Mackerras's avatar Paul Mackerras Committed by Michael Ellerman
Browse files

KVM: PPC: Book3S HV: Handle hypercalls correctly when nested 



When we are running as a nested hypervisor, we use a hypercall to
enter the guest rather than code in book3s_hv_rmhandlers.S.  This means
that the hypercall handlers listed in hcall_real_table never get called.
There are some hypercalls that are handled there and not in
kvmppc_pseries_do_hcall(), which therefore won't get processed for
a nested guest.

To fix this, we add cases to kvmppc_pseries_do_hcall() to handle those
hypercalls, with the following exceptions:

- The HPT hypercalls (H_ENTER, H_REMOVE, etc.) are not handled because
  we only support radix mode for nested guests.

- H_CEDE has to be handled specially because the cede logic in
  kvmhv_run_single_vcpu assumes that it has been processed by the time
  that kvmhv_p9_guest_entry() returns.  Therefore we put a special
  case for H_CEDE in kvmhv_p9_guest_entry().

For the XICS hypercalls, if real-mode processing is enabled, then the
virtual-mode handlers assume that they are being called only to finish
up the operation.  Therefore we turn off the real-mode flag in the XICS
code when running as a nested hypervisor.

Reviewed-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent f3c18e93

arch/powerpc/include/asm/asm-prototypes.h

+4 −0
Original line number Diff line number Diff line
@@ -167,4 +167,8 @@ void kvmhv_load_guest_pmu(struct kvm_vcpu *vcpu); 


int __kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu);



long kvmppc_h_set_dabr(struct kvm_vcpu *vcpu, unsigned long dabr);

long kvmppc_h_set_xdabr(struct kvm_vcpu *vcpu, unsigned long dabr,

			unsigned long dabrx);



#endif /* _ASM_POWERPC_ASM_PROTOTYPES_H */

arch/powerpc/kvm/book3s_hv.c

+43 −0
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ 
#include <asm/reg.h>

#include <asm/ppc-opcode.h>

#include <asm/asm-prototypes.h>

#include <asm/archrandom.h>

#include <asm/debug.h>

#include <asm/disassemble.h>

#include <asm/cputable.h>
@@ -915,6 +916,19 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu) 
			break;

		}

		return RESUME_HOST;

	case H_SET_DABR:

		ret = kvmppc_h_set_dabr(vcpu, kvmppc_get_gpr(vcpu, 4));

		break;

	case H_SET_XDABR:

		ret = kvmppc_h_set_xdabr(vcpu, kvmppc_get_gpr(vcpu, 4),

						kvmppc_get_gpr(vcpu, 5));

		break;

	case H_GET_TCE:

		ret = kvmppc_h_get_tce(vcpu, kvmppc_get_gpr(vcpu, 4),

						kvmppc_get_gpr(vcpu, 5));

		if (ret == H_TOO_HARD)

			return RESUME_HOST;

		break;

	case H_PUT_TCE:

		ret = kvmppc_h_put_tce(vcpu, kvmppc_get_gpr(vcpu, 4),

						kvmppc_get_gpr(vcpu, 5),
@@ -938,6 +952,10 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu) 
		if (ret == H_TOO_HARD)

			return RESUME_HOST;

		break;

	case H_RANDOM:

		if (!powernv_get_random_long(&vcpu->arch.regs.gpr[4]))

			ret = H_HARDWARE;

		break;



	case H_SET_PARTITION_TABLE:

		ret = H_FUNCTION;
@@ -966,6 +984,24 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu) 
	return RESUME_GUEST;

}



/*

 * Handle H_CEDE in the nested virtualization case where we haven't

 * called the real-mode hcall handlers in book3s_hv_rmhandlers.S.

 * This has to be done early, not in kvmppc_pseries_do_hcall(), so

 * that the cede logic in kvmppc_run_single_vcpu() works properly.

 */

static void kvmppc_nested_cede(struct kvm_vcpu *vcpu)

{

	vcpu->arch.shregs.msr |= MSR_EE;

	vcpu->arch.ceded = 1;

	smp_mb();

	if (vcpu->arch.prodded) {

		vcpu->arch.prodded = 0;

		smp_mb();

		vcpu->arch.ceded = 0;

	}

}



static int kvmppc_hcall_impl_hv(unsigned long cmd)

{

	switch (cmd) {
@@ -3424,6 +3460,13 @@ int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit, 
		vcpu->arch.shregs.msr = vcpu->arch.regs.msr;

		vcpu->arch.shregs.dar = mfspr(SPRN_DAR);

		vcpu->arch.shregs.dsisr = mfspr(SPRN_DSISR);



		/* H_CEDE has to be handled now, not later */

		if (trap == BOOK3S_INTERRUPT_SYSCALL && !vcpu->arch.nested &&

		    kvmppc_get_gpr(vcpu, 3) == H_CEDE) {

			kvmppc_nested_cede(vcpu);

			trap = 0;

		}

	} else {

		trap = kvmhv_load_hv_regs_and_go(vcpu, time_limit, lpcr);

	}

arch/powerpc/kvm/book3s_hv_rmhandlers.S

+2 −0
Original line number Diff line number Diff line
@@ -2466,6 +2466,7 @@ hcall_real_table: 
hcall_real_table_end:



_GLOBAL(kvmppc_h_set_xdabr)

EXPORT_SYMBOL_GPL(kvmppc_h_set_xdabr)

	andi.	r0, r5, DABRX_USER | DABRX_KERNEL

	beq	6f

	li	r0, DABRX_USER | DABRX_KERNEL | DABRX_BTI
@@ -2475,6 +2476,7 @@ _GLOBAL(kvmppc_h_set_xdabr) 
	blr



_GLOBAL(kvmppc_h_set_dabr)

EXPORT_SYMBOL_GPL(kvmppc_h_set_dabr)

	li	r5, DABRX_USER | DABRX_KERNEL

3:

BEGIN_FTR_SECTION

arch/powerpc/kvm/book3s_xics.c

+2 −1
Original line number Diff line number Diff line
@@ -1390,7 +1390,8 @@ static int kvmppc_xics_create(struct kvm_device *dev, u32 type) 
	}



#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE

	if (cpu_has_feature(CPU_FTR_ARCH_206)) {

	if (cpu_has_feature(CPU_FTR_ARCH_206) &&

	    cpu_has_feature(CPU_FTR_HVMODE)) {

		/* Enable real mode support */

		xics->real_mode = ENABLE_REALMODE;

		xics->real_mode_dbg = DEBUG_REALMODE;

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