From 12bc5b4cd5e59b3f8689b71d9d038a55e2777cdc Mon Sep 17 00:00:00 2001 From: Maxim Levitsky Date: Thu, 11 Nov 2021 12:06:03 +0100 Subject: [PATCH] gdbstub, kvm: let KVM report supported singlestep flags MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Maxim Levitsky [Extracted from Maxim's patch into a separate commit. - Paolo] Signed-off-by: Paolo Bonzini Reviewed-by: Alex Bennée Message-Id: <20211111110604.207376-5-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini --- accel/kvm/kvm-all.c | 12 ++++++++++++ gdbstub.c | 10 +++++++++- include/sysemu/kvm.h | 15 +++++++++++++++ 3 files changed, 36 insertions(+), 1 deletion(-) diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index eecd8031cf..2f5597572a 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -168,6 +168,8 @@ bool kvm_vm_attributes_allowed; bool kvm_direct_msi_allowed; bool kvm_ioeventfd_any_length_allowed; bool kvm_msi_use_devid; +bool kvm_has_guest_debug; +int kvm_sstep_flags; static bool kvm_immediate_exit; static hwaddr kvm_max_slot_size = ~0; @@ -2564,6 +2566,16 @@ static int kvm_init(MachineState *ms) kvm_ioeventfd_any_length_allowed = (kvm_check_extension(s, KVM_CAP_IOEVENTFD_ANY_LENGTH) > 0); +#ifdef KVM_CAP_SET_GUEST_DEBUG + kvm_has_guest_debug = + (kvm_check_extension(s, KVM_CAP_SET_GUEST_DEBUG) > 0); +#endif + + kvm_sstep_flags = 0; + if (kvm_has_guest_debug) { + kvm_sstep_flags = SSTEP_ENABLE; + } + kvm_state = s; ret = kvm_arch_init(ms, s); diff --git a/gdbstub.c b/gdbstub.c index a955175fd4..3c14c6a038 100644 --- a/gdbstub.c +++ b/gdbstub.c @@ -391,6 +391,8 @@ static void init_gdbserver_state(void) */ if (replay_mode != REPLAY_MODE_NONE) { gdbserver_state.supported_sstep_flags = SSTEP_ENABLE; + } else if (kvm_enabled()) { + gdbserver_state.supported_sstep_flags = kvm_get_supported_sstep_flags(); } else { gdbserver_state.supported_sstep_flags = SSTEP_ENABLE | SSTEP_NOIRQ | SSTEP_NOTIMER; @@ -400,7 +402,8 @@ static void init_gdbserver_state(void) * By default use no IRQs and no timers while single stepping so as to * make single stepping like an ICE HW step. */ - gdbserver_state.sstep_flags = gdbserver_state.supported_sstep_flags; + gdbserver_state.sstep_flags = SSTEP_ENABLE | SSTEP_NOIRQ | SSTEP_NOTIMER; + gdbserver_state.sstep_flags &= gdbserver_state.supported_sstep_flags; } @@ -3520,6 +3523,11 @@ int gdbserver_start(const char *device) return -1; } + if (kvm_enabled() && !kvm_supports_guest_debug()) { + error_report("gdbstub: KVM doesn't support guest debugging"); + return -1; + } + if (!device) return -1; if (strcmp(device, "none") != 0) { diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h index 7b22aeb6ae..6eb39a088b 100644 --- a/include/sysemu/kvm.h +++ b/include/sysemu/kvm.h @@ -46,6 +46,8 @@ extern bool kvm_readonly_mem_allowed; extern bool kvm_direct_msi_allowed; extern bool kvm_ioeventfd_any_length_allowed; extern bool kvm_msi_use_devid; +extern bool kvm_has_guest_debug; +extern int kvm_sstep_flags; #define kvm_enabled() (kvm_allowed) /** @@ -167,6 +169,17 @@ extern bool kvm_msi_use_devid; */ #define kvm_msi_devid_required() (kvm_msi_use_devid) +/* + * Does KVM support guest debugging + */ +#define kvm_supports_guest_debug() (kvm_has_guest_debug) + +/* + * kvm_supported_sstep_flags + * Returns: SSTEP_* flags that KVM supports for guest debug + */ +#define kvm_get_supported_sstep_flags() (kvm_sstep_flags) + #else #define kvm_enabled() (0) @@ -184,6 +197,8 @@ extern bool kvm_msi_use_devid; #define kvm_direct_msi_enabled() (false) #define kvm_ioeventfd_any_length_enabled() (false) #define kvm_msi_devid_required() (false) +#define kvm_supports_guest_debug() (false) +#define kvm_get_supported_sstep_flags() (0) #endif /* CONFIG_KVM_IS_POSSIBLE */