hw/ppc/spapr.c | 1 + hw/ppc/spapr_caps.c | 30 ++++++++++++++++++++++++++++++ include/hw/ppc/spapr.h | 3 ++- target/ppc/kvm.c | 12 ++++++++++++ target/ppc/kvm_ppc.h | 12 ++++++++++++ 5 files changed, 57 insertions(+), 1 deletion(-)
Making use of ppc's Protected Execution Facility (PEF) feature, a
guest can become a secure guest (aka. secure VM - SVM) and have its
memory protected from access by the host. This feature is mediated by
a piece of firmware called the Ultravisor (UV).
The transition from a regular to a secure VM is initiated by the guest
kernel during prom_init via the use of an ultracall (enter secure mode
- UV_ESM) and with cooperation from the hypervisor via an hcall
(H_SVM_INIT_START).
Currently QEMU has no knowledge of this process and no way to
determine if a host supports the feature. A guest with PEF support
enabled would always try to enter secure mode regardless of user
intent or hardware support.
To address the above, a new KVM capability (KVM_CAP_PPC_SECURE_GUEST
[1]) is being introduced in the kernel without which KVM will block
the secure transition.
This patch adds support for checking/enabling this KVM capability via
a new spapr capability (SPAPR_CAP_SECURE_GUEST) and the equivalent
command line switch (-machine pseries,cap-svm). The capability
defaults to off.
1- https://lore.kernel.org/kvm/20200319043301.GA13052@blackberry
Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
---
I have implemented this to be able to test Paul's patch. I'm sending
it as RFC in case it helps anyone else and if we decide to go in this
direction I can develop it further.
PS: TCG currently gets in a loop of 0x700 due to the lack of 'sc 2'
emulation - and all the rest of PEF, of course =).
---
hw/ppc/spapr.c | 1 +
hw/ppc/spapr_caps.c | 30 ++++++++++++++++++++++++++++++
include/hw/ppc/spapr.h | 3 ++-
target/ppc/kvm.c | 12 ++++++++++++
target/ppc/kvm_ppc.h | 12 ++++++++++++
5 files changed, 57 insertions(+), 1 deletion(-)
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 9a2bd501aa..a881ac4e29 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -4542,6 +4542,7 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
smc->default_caps.caps[SPAPR_CAP_LARGE_DECREMENTER] = SPAPR_CAP_ON;
smc->default_caps.caps[SPAPR_CAP_CCF_ASSIST] = SPAPR_CAP_ON;
smc->default_caps.caps[SPAPR_CAP_FWNMI] = SPAPR_CAP_ON;
+ smc->default_caps.caps[SPAPR_CAP_SECURE_GUEST] = SPAPR_CAP_OFF;
spapr_caps_add_properties(smc, &error_abort);
smc->irq = &spapr_irq_dual;
smc->dr_phb_enabled = true;
diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c
index 679ae7959f..375b7e0b30 100644
--- a/hw/ppc/spapr_caps.c
+++ b/hw/ppc/spapr_caps.c
@@ -524,6 +524,27 @@ static void cap_fwnmi_apply(SpaprMachineState *spapr, uint8_t val,
}
}
+static void cap_secure_guest_apply(SpaprMachineState *spapr,
+ uint8_t val, Error **errp)
+{
+ if (!val) {
+ /* capability disabled by default */
+ return;
+ }
+
+ if (!kvm_enabled()) {
+ error_setg(errp, "No PEF support in tcg, try cap-svm=off");
+ return;
+ }
+
+ if (!kvmppc_has_cap_secure_guest()) {
+ error_setg(errp, "KVM implementation does not support secure guests, "
+ "try cap-svm=off");
+ } else if (kvmppc_enable_cap_secure_guest() < 0) {
+ error_setg(errp, "Error enabling cap-svm, try cap-svm=off");
+ }
+}
+
SpaprCapabilityInfo capability_table[SPAPR_CAP_NUM] = {
[SPAPR_CAP_HTM] = {
.name = "htm",
@@ -632,6 +653,15 @@ SpaprCapabilityInfo capability_table[SPAPR_CAP_NUM] = {
.type = "bool",
.apply = cap_fwnmi_apply,
},
+ [SPAPR_CAP_SECURE_GUEST] = {
+ .name = "svm",
+ .description = "Allow the guest to become a Secure Guest",
+ .index = SPAPR_CAP_SECURE_GUEST,
+ .get = spapr_cap_get_bool,
+ .set = spapr_cap_set_bool,
+ .type = "bool",
+ .apply = cap_secure_guest_apply,
+ },
};
static SpaprCapabilities default_caps_with_cpu(SpaprMachineState *spapr,
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 42d64a0368..7f5289782d 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -81,8 +81,9 @@ typedef enum {
#define SPAPR_CAP_CCF_ASSIST 0x09
/* Implements PAPR FWNMI option */
#define SPAPR_CAP_FWNMI 0x0A
+#define SPAPR_CAP_SECURE_GUEST 0x0B
/* Num Caps */
-#define SPAPR_CAP_NUM (SPAPR_CAP_FWNMI + 1)
+#define SPAPR_CAP_NUM (SPAPR_CAP_SECURE_GUEST + 1)
/*
* Capability Values
diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
index 597f72be1b..9254749cd7 100644
--- a/target/ppc/kvm.c
+++ b/target/ppc/kvm.c
@@ -88,6 +88,7 @@ static int cap_ppc_safe_indirect_branch;
static int cap_ppc_count_cache_flush_assist;
static int cap_ppc_nested_kvm_hv;
static int cap_large_decr;
+static int cap_ppc_secure_guest;
static uint32_t debug_inst_opcode;
@@ -135,6 +136,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
cap_resize_hpt = kvm_vm_check_extension(s, KVM_CAP_SPAPR_RESIZE_HPT);
kvmppc_get_cpu_characteristics(s);
cap_ppc_nested_kvm_hv = kvm_vm_check_extension(s, KVM_CAP_PPC_NESTED_HV);
+ cap_ppc_secure_guest = kvm_vm_check_extension(s, KVM_CAP_PPC_SECURE_GUEST);
cap_large_decr = kvmppc_get_dec_bits();
/*
* Note: setting it to false because there is not such capability
@@ -2532,6 +2534,16 @@ int kvmppc_enable_cap_large_decr(PowerPCCPU *cpu, int enable)
return 0;
}
+bool kvmppc_has_cap_secure_guest(void)
+{
+ return !!cap_ppc_secure_guest;
+}
+
+int kvmppc_enable_cap_secure_guest(void)
+{
+ return kvm_vm_enable_cap(kvm_state, KVM_CAP_PPC_SECURE_GUEST, 0, 1);
+}
+
PowerPCCPUClass *kvm_ppc_get_host_cpu_class(void)
{
uint32_t host_pvr = mfpvr();
diff --git a/target/ppc/kvm_ppc.h b/target/ppc/kvm_ppc.h
index 332fa0aa1c..a9a3aa67c6 100644
--- a/target/ppc/kvm_ppc.h
+++ b/target/ppc/kvm_ppc.h
@@ -72,6 +72,8 @@ int kvmppc_set_cap_nested_kvm_hv(int enable);
int kvmppc_get_cap_large_decr(void);
int kvmppc_enable_cap_large_decr(PowerPCCPU *cpu, int enable);
int kvmppc_enable_hwrng(void);
+bool kvmppc_has_cap_secure_guest(void);
+int kvmppc_enable_cap_secure_guest(void);
int kvmppc_put_books_sregs(PowerPCCPU *cpu);
PowerPCCPUClass *kvm_ppc_get_host_cpu_class(void);
void kvmppc_check_papr_resize_hpt(Error **errp);
@@ -380,6 +382,16 @@ static inline int kvmppc_enable_cap_large_decr(PowerPCCPU *cpu, int enable)
return -1;
}
+static inline bool kvmppc_has_cap_secure_guest(void)
+{
+ return false;
+}
+
+static inline int kvmppc_enable_cap_secure_guest(void)
+{
+ return -1;
+}
+
static inline int kvmppc_enable_hwrng(void)
{
return -1;
--
2.23.0
On Fri, Mar 20, 2020 at 08:23:53PM -0300, Fabiano Rosas wrote:
> Making use of ppc's Protected Execution Facility (PEF) feature, a
> guest can become a secure guest (aka. secure VM - SVM) and have its
> memory protected from access by the host. This feature is mediated by
> a piece of firmware called the Ultravisor (UV).
>
> The transition from a regular to a secure VM is initiated by the guest
> kernel during prom_init via the use of an ultracall (enter secure mode
> - UV_ESM) and with cooperation from the hypervisor via an hcall
> (H_SVM_INIT_START).
>
> Currently QEMU has no knowledge of this process and no way to
> determine if a host supports the feature. A guest with PEF support
> enabled would always try to enter secure mode regardless of user
> intent or hardware support.
>
> To address the above, a new KVM capability (KVM_CAP_PPC_SECURE_GUEST
> [1]) is being introduced in the kernel without which KVM will block
> the secure transition.
>
> This patch adds support for checking/enabling this KVM capability via
> a new spapr capability (SPAPR_CAP_SECURE_GUEST) and the equivalent
> command line switch (-machine pseries,cap-svm). The capability
> defaults to off.
>
> 1- https://lore.kernel.org/kvm/20200319043301.GA13052@blackberry
>
> Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
> ---
>
> I have implemented this to be able to test Paul's patch. I'm sending
> it as RFC in case it helps anyone else and if we decide to go in this
> direction I can develop it further.
LGTM
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
It will miss the qemu-5.0 cut-off, of course, but that should be ok.
>
> PS: TCG currently gets in a loop of 0x700 due to the lack of 'sc 2'
> emulation - and all the rest of PEF, of course =).
>
> ---
> hw/ppc/spapr.c | 1 +
> hw/ppc/spapr_caps.c | 30 ++++++++++++++++++++++++++++++
> include/hw/ppc/spapr.h | 3 ++-
> target/ppc/kvm.c | 12 ++++++++++++
> target/ppc/kvm_ppc.h | 12 ++++++++++++
> 5 files changed, 57 insertions(+), 1 deletion(-)
>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 9a2bd501aa..a881ac4e29 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -4542,6 +4542,7 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
> smc->default_caps.caps[SPAPR_CAP_LARGE_DECREMENTER] = SPAPR_CAP_ON;
> smc->default_caps.caps[SPAPR_CAP_CCF_ASSIST] = SPAPR_CAP_ON;
> smc->default_caps.caps[SPAPR_CAP_FWNMI] = SPAPR_CAP_ON;
> + smc->default_caps.caps[SPAPR_CAP_SECURE_GUEST] = SPAPR_CAP_OFF;
> spapr_caps_add_properties(smc, &error_abort);
> smc->irq = &spapr_irq_dual;
> smc->dr_phb_enabled = true;
> diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c
> index 679ae7959f..375b7e0b30 100644
> --- a/hw/ppc/spapr_caps.c
> +++ b/hw/ppc/spapr_caps.c
> @@ -524,6 +524,27 @@ static void cap_fwnmi_apply(SpaprMachineState *spapr, uint8_t val,
> }
> }
>
> +static void cap_secure_guest_apply(SpaprMachineState *spapr,
> + uint8_t val, Error **errp)
> +{
> + if (!val) {
> + /* capability disabled by default */
> + return;
> + }
> +
> + if (!kvm_enabled()) {
> + error_setg(errp, "No PEF support in tcg, try cap-svm=off");
> + return;
> + }
> +
> + if (!kvmppc_has_cap_secure_guest()) {
> + error_setg(errp, "KVM implementation does not support secure guests, "
> + "try cap-svm=off");
> + } else if (kvmppc_enable_cap_secure_guest() < 0) {
> + error_setg(errp, "Error enabling cap-svm, try cap-svm=off");
> + }
> +}
> +
> SpaprCapabilityInfo capability_table[SPAPR_CAP_NUM] = {
> [SPAPR_CAP_HTM] = {
> .name = "htm",
> @@ -632,6 +653,15 @@ SpaprCapabilityInfo capability_table[SPAPR_CAP_NUM] = {
> .type = "bool",
> .apply = cap_fwnmi_apply,
> },
> + [SPAPR_CAP_SECURE_GUEST] = {
> + .name = "svm",
> + .description = "Allow the guest to become a Secure Guest",
> + .index = SPAPR_CAP_SECURE_GUEST,
> + .get = spapr_cap_get_bool,
> + .set = spapr_cap_set_bool,
> + .type = "bool",
> + .apply = cap_secure_guest_apply,
> + },
> };
>
> static SpaprCapabilities default_caps_with_cpu(SpaprMachineState *spapr,
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index 42d64a0368..7f5289782d 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -81,8 +81,9 @@ typedef enum {
> #define SPAPR_CAP_CCF_ASSIST 0x09
> /* Implements PAPR FWNMI option */
> #define SPAPR_CAP_FWNMI 0x0A
> +#define SPAPR_CAP_SECURE_GUEST 0x0B
> /* Num Caps */
> -#define SPAPR_CAP_NUM (SPAPR_CAP_FWNMI + 1)
> +#define SPAPR_CAP_NUM (SPAPR_CAP_SECURE_GUEST + 1)
>
> /*
> * Capability Values
> diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
> index 597f72be1b..9254749cd7 100644
> --- a/target/ppc/kvm.c
> +++ b/target/ppc/kvm.c
> @@ -88,6 +88,7 @@ static int cap_ppc_safe_indirect_branch;
> static int cap_ppc_count_cache_flush_assist;
> static int cap_ppc_nested_kvm_hv;
> static int cap_large_decr;
> +static int cap_ppc_secure_guest;
>
> static uint32_t debug_inst_opcode;
>
> @@ -135,6 +136,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
> cap_resize_hpt = kvm_vm_check_extension(s, KVM_CAP_SPAPR_RESIZE_HPT);
> kvmppc_get_cpu_characteristics(s);
> cap_ppc_nested_kvm_hv = kvm_vm_check_extension(s, KVM_CAP_PPC_NESTED_HV);
> + cap_ppc_secure_guest = kvm_vm_check_extension(s, KVM_CAP_PPC_SECURE_GUEST);
> cap_large_decr = kvmppc_get_dec_bits();
> /*
> * Note: setting it to false because there is not such capability
> @@ -2532,6 +2534,16 @@ int kvmppc_enable_cap_large_decr(PowerPCCPU *cpu, int enable)
> return 0;
> }
>
> +bool kvmppc_has_cap_secure_guest(void)
> +{
> + return !!cap_ppc_secure_guest;
> +}
> +
> +int kvmppc_enable_cap_secure_guest(void)
> +{
> + return kvm_vm_enable_cap(kvm_state, KVM_CAP_PPC_SECURE_GUEST, 0, 1);
> +}
> +
> PowerPCCPUClass *kvm_ppc_get_host_cpu_class(void)
> {
> uint32_t host_pvr = mfpvr();
> diff --git a/target/ppc/kvm_ppc.h b/target/ppc/kvm_ppc.h
> index 332fa0aa1c..a9a3aa67c6 100644
> --- a/target/ppc/kvm_ppc.h
> +++ b/target/ppc/kvm_ppc.h
> @@ -72,6 +72,8 @@ int kvmppc_set_cap_nested_kvm_hv(int enable);
> int kvmppc_get_cap_large_decr(void);
> int kvmppc_enable_cap_large_decr(PowerPCCPU *cpu, int enable);
> int kvmppc_enable_hwrng(void);
> +bool kvmppc_has_cap_secure_guest(void);
> +int kvmppc_enable_cap_secure_guest(void);
> int kvmppc_put_books_sregs(PowerPCCPU *cpu);
> PowerPCCPUClass *kvm_ppc_get_host_cpu_class(void);
> void kvmppc_check_papr_resize_hpt(Error **errp);
> @@ -380,6 +382,16 @@ static inline int kvmppc_enable_cap_large_decr(PowerPCCPU *cpu, int enable)
> return -1;
> }
>
> +static inline bool kvmppc_has_cap_secure_guest(void)
> +{
> + return false;
> +}
> +
> +static inline int kvmppc_enable_cap_secure_guest(void)
> +{
> + return -1;
> +}
> +
> static inline int kvmppc_enable_hwrng(void)
> {
> return -1;
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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