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KVM: arm64: Fix nVHE hyp panic host context restore 

When panicking from the nVHE hyp and restoring the host context, x29 is
expected to hold a pointer to the host context. This wasn't being done
so fix it to make sure there's a valid pointer the host context being
used.

Rather than passing a boolean indicating whether or not the host context
should be restored, instead pass the pointer to the host context. NULL
is passed to indicate that no context should be restored.

Fixes: a2e102e20f ("KVM: arm64: nVHE: Handle hyp panics")
Cc: stable@vger.kernel.org
Signed-off-by: Andrew Scull <ascull@google.com>
[maz: partial rewrite to fit 5.12-rc1]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210219122406.1337626-1-ascull@google.com
Message-Id: <20210305185254.3730990-4-maz@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Andrew Scull 2021-03-05 18:52:49 +00:00 committed by Paolo Bonzini
parent 31948332d5
commit c4b000c392
3 changed files with 11 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
arch/arm64/include/asm/kvm_hyp.h
View File

@ -102,7 +102,8 @@ bool kvm_host_psci_handler(struct kvm_cpu_context *host_ctxt);
void __noreturn hyp_panic(void);
#ifdef __KVM_NVHE_HYPERVISOR__
void __noreturn __hyp_do_panic(bool restore_host, u64 spsr, u64 elr, u64 par);
void __noreturn __hyp_do_panic(struct kvm_cpu_context *host_ctxt, u64 spsr,
u64 elr, u64 par);
#endif
#endif /* __ARM64_KVM_HYP_H__ */

15
arch/arm64/kvm/hyp/nvhe/host.S
View File

@ -71,7 +71,8 @@ SYM_FUNC_START(__host_enter)
SYM_FUNC_END(__host_enter)
/*
* void __noreturn __hyp_do_panic(bool restore_host, u64 spsr, u64 elr, u64 par);
* void __noreturn __hyp_do_panic(struct kvm_cpu_context *host_ctxt, u64 spsr,
* u64 elr, u64 par);
*/
SYM_FUNC_START(__hyp_do_panic)
/* Prepare and exit to the host's panic funciton. */
@ -82,9 +83,11 @@ SYM_FUNC_START(__hyp_do_panic)
hyp_kimg_va lr, x6
msr elr_el2, lr
/* Set the panic format string. Use the, now free, LR as scratch. */
ldr lr, =__hyp_panic_string
hyp_kimg_va lr, x6
mov x29, x0
/* Load the format string into x0 and arguments into x1-7 */
ldr x0, =__hyp_panic_string
hyp_kimg_va x0, x6
/* Load the format arguments into x1-7. */
mov x6, x3
@ -94,9 +97,7 @@ SYM_FUNC_START(__hyp_do_panic)
mrs x5, hpfar_el2
/* Enter the host, conditionally restoring the host context. */
cmp x0, xzr
mov x0, lr
b.eq __host_enter_without_restoring
cbz x29, __host_enter_without_restoring
b __host_enter_for_panic
SYM_FUNC_END(__hyp_do_panic)

3
arch/arm64/kvm/hyp/nvhe/switch.c
View File

@ -266,7 +266,6 @@ void __noreturn hyp_panic(void)
u64 spsr = read_sysreg_el2(SYS_SPSR);
u64 elr = read_sysreg_el2(SYS_ELR);
u64 par = read_sysreg_par();
bool restore_host = true;
struct kvm_cpu_context *host_ctxt;
struct kvm_vcpu *vcpu;
@ -280,7 +279,7 @@ void __noreturn hyp_panic(void)
__sysreg_restore_state_nvhe(host_ctxt);
}
__hyp_do_panic(restore_host, spsr, elr, par);
__hyp_do_panic(host_ctxt, spsr, elr, par);
unreachable();
}