KVM: PPC: Book3S HV: Save/restore host values of debug registers

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At present, HV KVM on POWER8 and POWER9 machines loses any instruction
or data breakpoint set in the host whenever a guest is run.
Instruction breakpoints are currently only used by xmon, but ptrace
and the perf_event subsystem can set data breakpoints as well as xmon.

To fix this, we save the host values of the debug registers (CIABR,
DAWR and DAWRX) before entering the guest and restore them on exit.
To provide space to save them in the stack frame, we expand the stack
frame allocated by kvmppc_hv_entry() from 112 to 144 bytes.

Fixes: b005255e12 ("KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs", 2014-01-08)
Cc: stable@vger.kernel.org # v3.14+
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

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Paul Mackerras 2017-06-16 11:53:19 +10:00

parent 46a704f840

commit 7ceaa6dcd8

1 changed files with 32 additions and 13 deletions

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arch/powerpc/kvm/book3s_hv_rmhandlers.S

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