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| author | James Morse <james.morse@arm.com> | 2019-06-18 16:17:36 +0100 |
|---|---|---|
| committer | Marc Zyngier <marc.zyngier@arm.com> | 2019-07-05 13:03:29 +0100 |
| commit | 0e5b9c085dcef61163f3f277964c1a1623043f67 (patch) | |
| tree | 703a97a9a895dd5829f89ef5fbb5872ae8e690b0 | |
| parent | 5d994374e872bef1bba25c80950af6a77ea470e1 (diff) | |
| download | linux-0e5b9c085dcef61163f3f277964c1a1623043f67.tar.bz2 | |
KVM: arm64: Consume pending SError as early as possible
On systems with v8.2 we switch the 'vaxorcism' of guest SError with an
alternative sequence that uses the ESB-instruction, then reads DISR_EL1.
This saves the unmasking and remasking of asynchronous exceptions.
We do this after we've saved the guest registers and restored the
host's. Any SError that becomes pending due to this will be accounted
to the guest, when it actually occurred during host-execution.
Move the ESB-instruction as early as possible. Any guest SError
will become pending due to this ESB-instruction and then consumed to
DISR_EL1 before the host touches anything.
This lets us account for host/guest SError precisely on the guest
exit exception boundary.
Because the ESB-instruction now lands in the preamble section of
the vectors, we need to add it to the unpatched indirect vectors
too, and to any sequence that may be patched in over the top.
The ESB-instruction always lives in the head of the vectors,
to be before any memory write. Whereas the register-store always
lives in the tail.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
| -rw-r--r-- | arch/arm64/include/asm/kvm_asm.h | 2 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/entry.S | 5 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/hyp-entry.S | 6 |
3 files changed, 8 insertions, 5 deletions
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index 388e1b520618..44a243754c1b 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -34,7 +34,7 @@ * Size of the HYP vectors preamble. kvm_patch_vector_branch() generates code * that jumps over this. */ -#define KVM_VECTOR_PREAMBLE (1 * AARCH64_INSN_SIZE) +#define KVM_VECTOR_PREAMBLE (2 * AARCH64_INSN_SIZE) #ifndef __ASSEMBLY__ diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S index bd34016354ba..fb2e218ce0c7 100644 --- a/arch/arm64/kvm/hyp/entry.S +++ b/arch/arm64/kvm/hyp/entry.S @@ -127,8 +127,8 @@ ENTRY(__guest_exit) alternative_if ARM64_HAS_RAS_EXTN // If we have the RAS extensions we can consume a pending error - // without an unmask-SError and isb. - esb + // without an unmask-SError and isb. The ESB-instruction consumed any + // pending guest error when we took the exception from the guest. mrs_s x2, SYS_DISR_EL1 str x2, [x1, #(VCPU_FAULT_DISR - VCPU_CONTEXT)] cbz x2, 1f @@ -146,7 +146,6 @@ alternative_else mov x5, x0 dsb sy // Synchronize against in-flight ld/st - nop msr daifclr, #4 // Unmask aborts alternative_endif diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S index a911b8ffc0f3..ffa68d5713f1 100644 --- a/arch/arm64/kvm/hyp/hyp-entry.S +++ b/arch/arm64/kvm/hyp/hyp-entry.S @@ -226,6 +226,7 @@ ENDPROC(\label) .macro valid_vect target .align 7 661: + esb stp x0, x1, [sp, #-16]! 662: b \target @@ -237,6 +238,7 @@ check_preamble_length 661b, 662b .align 7 661: b \target + nop 662: ldp x0, x1, [sp], #16 b \target @@ -269,7 +271,8 @@ ENDPROC(__kvm_hyp_vector) #ifdef CONFIG_KVM_INDIRECT_VECTORS .macro hyp_ventry .align 7 -1: .rept 27 +1: esb + .rept 26 nop .endr /* @@ -317,6 +320,7 @@ ENTRY(__bp_harden_hyp_vecs_end) .popsection ENTRY(__smccc_workaround_1_smc_start) + esb sub sp, sp, #(8 * 4) stp x2, x3, [sp, #(8 * 0)] stp x0, x1, [sp, #(8 * 2)] |