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KVM: PPC: Book3S HV nestedv2: Get the PID only if needed to copy tofrom a guest

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kvmhv_copy_tofrom_guest_radix() gets the PID at the start of the
function. If pid is not used, then this is a wasteful H_GUEST_GET_STATE
hcall for nestedv2 hosts. Move the assignment to where pid will be used.

Suggested-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231201132618.555031-5-vaibhav@linux.ibm.com
This commit is contained in:
Jordan Niethe 2023-12-01 18:56:09 +05:30 committed by Michael Ellerman
parent 63ccae78cd
commit e678748a8d
1 changed files with 3 additions and 1 deletions
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4
arch/powerpc/kvm/book3s_64_mmu_radix.c
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@ -97,7 +97,7 @@ static long kvmhv_copy_tofrom_guest_radix(struct kvm_vcpu *vcpu, gva_t eaddr,
void *to, void *from, unsigned long n)
{
int lpid = vcpu->kvm->arch.lpid;
int pid = kvmppc_get_pid(vcpu);
int pid;
/* This would cause a data segment intr so don't allow the access */
if (eaddr & (0x3FFUL << 52))
@ -110,6 +110,8 @@ static long kvmhv_copy_tofrom_guest_radix(struct kvm_vcpu *vcpu, gva_t eaddr,
/* If accessing quadrant 3 then pid is expected to be 0 */
if (((eaddr >> 62) & 0x3) == 0x3)
pid = 0;
else
pid = kvmppc_get_pid(vcpu);
eaddr &= ~(0xFFFUL << 52);