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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH RFC v12 16/21] pvh: Use PV handlers for emulated forced invalid ops, cpuid, and IO
This means putting hooks into the vmexit handlers to call them instead
of the HVM ones.
It also means calling raw_copy_from_guest() rather than
copy_from_user(), and delivering page faults during PV emulation to
guests using the HVM injection path rather than the PV one for PVH
guests.
Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
Signed-off-by: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>
CC: Jan Beulich <jan.beulich@xxxxxxxx>
CC: Tim Deegan <tim@xxxxxxx>
CC: Keir Fraser <keir@xxxxxxx>
---
xen/arch/x86/hvm/vmx/vmx.c | 58 +++++++++++++++++++++++++++++----------
xen/arch/x86/traps.c | 28 ++++++++++++++-----
xen/include/asm-x86/processor.h | 2 ++
xen/include/asm-x86/traps.h | 3 ++
4 files changed, 70 insertions(+), 21 deletions(-)
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index b3f933a..0fa2d0b 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -56,6 +56,7 @@
#include <asm/apic.h>
#include <asm/hvm/nestedhvm.h>
#include <asm/event.h>
+#include <asm/traps.h>
enum handler_return { HNDL_done, HNDL_unhandled, HNDL_exception_raised };
@@ -2669,8 +2670,16 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
/* Already handled above. */
break;
case TRAP_invalid_op:
- HVMTRACE_1D(TRAP, vector);
- vmx_vmexit_ud_intercept(regs);
+ if ( is_pvh_vcpu(v) )
+ {
+ if ( !emulate_forced_invalid_op(regs) )
+ hvm_inject_hw_exception(TRAP_invalid_op,
HVM_DELIVER_NO_ERROR_CODE);
+ }
+ else
+ {
+ HVMTRACE_1D(TRAP, vector);
+ vmx_vmexit_ud_intercept(regs);
+ }
break;
default:
HVMTRACE_1D(TRAP, vector);
@@ -2719,8 +2728,8 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
break;
}
case EXIT_REASON_CPUID:
+ is_pvh_vcpu(v) ? pv_cpuid(regs) : vmx_do_cpuid(regs);
update_guest_eip(); /* Safe: CPUID */
- vmx_do_cpuid(regs);
break;
case EXIT_REASON_HLT:
update_guest_eip(); /* Safe: HLT */
@@ -2868,21 +2877,42 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
}
case EXIT_REASON_IO_INSTRUCTION:
- exit_qualification = __vmread(EXIT_QUALIFICATION);
- if ( exit_qualification & 0x10 )
+ if ( is_pvh_vcpu(v) )
{
- /* INS, OUTS */
- if ( !handle_mmio() )
- hvm_inject_hw_exception(TRAP_gp_fault, 0);
+ /*
+ * Note: A PVH guest sets IOPL natively by setting bits in
+ * the eflags, and not via hypercalls used by a PV.
+ */
+ struct segment_register seg;
+ int requested = (regs->rflags & X86_EFLAGS_IOPL) >> 12;
+ int curr_lvl = (regs->rflags & X86_EFLAGS_VM) ? 3 : 0;
+
+ if ( curr_lvl == 0 )
+ {
+ hvm_get_segment_register(current, x86_seg_ss, &seg);
+ curr_lvl = seg.attr.fields.dpl;
+ }
+ if ( requested < curr_lvl || !emulate_privileged_op(regs) )
+ hvm_inject_hw_exception(TRAP_gp_fault, regs->error_code);
}
else
{
- /* IN, OUT */
- uint16_t port = (exit_qualification >> 16) & 0xFFFF;
- int bytes = (exit_qualification & 0x07) + 1;
- int dir = (exit_qualification & 0x08) ? IOREQ_READ : IOREQ_WRITE;
- if ( handle_pio(port, bytes, dir) )
- update_guest_eip(); /* Safe: IN, OUT */
+ exit_qualification = __vmread(EXIT_QUALIFICATION);
+ if ( exit_qualification & 0x10 )
+ {
+ /* INS, OUTS */
+ if ( !handle_mmio() )
+ hvm_inject_hw_exception(TRAP_gp_fault, 0);
+ }
+ else
+ {
+ /* IN, OUT */
+ uint16_t port = (exit_qualification >> 16) & 0xFFFF;
+ int bytes = (exit_qualification & 0x07) + 1;
+ int dir = (exit_qualification & 0x08) ? IOREQ_READ :
IOREQ_WRITE;
+ if ( handle_pio(port, bytes, dir) )
+ update_guest_eip(); /* Safe: IN, OUT */
+ }
}
break;
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index 35d4a3e..683ef8f 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -738,7 +738,7 @@ int cpuid_hypervisor_leaves( uint32_t idx, uint32_t sub_idx,
return 1;
}
-static void pv_cpuid(struct cpu_user_regs *regs)
+void pv_cpuid(struct cpu_user_regs *regs)
{
uint32_t a, b, c, d;
@@ -915,7 +915,7 @@ static int emulate_invalid_rdtscp(struct cpu_user_regs
*regs)
return EXCRET_fault_fixed;
}
-static int emulate_forced_invalid_op(struct cpu_user_regs *regs)
+int emulate_forced_invalid_op(struct cpu_user_regs *regs)
{
char sig[5], instr[2];
unsigned long eip, rc;
@@ -923,7 +923,7 @@ static int emulate_forced_invalid_op(struct cpu_user_regs
*regs)
eip = regs->eip;
/* Check for forced emulation signature: ud2 ; .ascii "xen". */
- if ( (rc = copy_from_user(sig, (char *)eip, sizeof(sig))) != 0 )
+ if ( (rc = raw_copy_from_guest(sig, (char *)eip, sizeof(sig))) != 0 )
{
propagate_page_fault(eip + sizeof(sig) - rc, 0);
return EXCRET_fault_fixed;
@@ -933,7 +933,7 @@ static int emulate_forced_invalid_op(struct cpu_user_regs
*regs)
eip += sizeof(sig);
/* We only emulate CPUID. */
- if ( ( rc = copy_from_user(instr, (char *)eip, sizeof(instr))) != 0 )
+ if ( ( rc = raw_copy_from_guest(instr, (char *)eip, sizeof(instr))) != 0 )
{
propagate_page_fault(eip + sizeof(instr) - rc, 0);
return EXCRET_fault_fixed;
@@ -1072,7 +1072,7 @@ static void reserved_bit_page_fault(
show_execution_state(regs);
}
-void propagate_page_fault(unsigned long addr, u16 error_code)
+static void pv_inject_page_fault(unsigned long addr, u16 error_code)
{
struct trap_info *ti;
struct vcpu *v = current;
@@ -1106,6 +1106,13 @@ void propagate_page_fault(unsigned long addr, u16
error_code)
reserved_bit_page_fault(addr, guest_cpu_user_regs());
}
+void propagate_page_fault(unsigned long addr, u16 error_code)
+{
+ is_pvh_vcpu(current)
+ ? hvm_inject_page_fault(error_code, addr)
+ : pv_inject_page_fault(addr, error_code);
+}
+
static int handle_gdt_ldt_mapping_fault(
unsigned long offset, struct cpu_user_regs *regs)
{
@@ -1624,6 +1631,13 @@ static int guest_io_okay(
int user_mode = !(v->arch.flags & TF_kernel_mode);
#define TOGGLE_MODE() if ( user_mode ) toggle_guest_mode(v)
+ /*
+ * For PVH we check this in vmexit for EXIT_REASON_IO_INSTRUCTION
+ * and so don't need to check again here.
+ */
+ if ( is_pvh_vcpu(v) )
+ return 1;
+
if ( !vm86_mode(regs) &&
(v->arch.pv_vcpu.iopl >= (guest_kernel_mode(v, regs) ? 1 : 3)) )
return 1;
@@ -1869,7 +1883,7 @@ static inline uint64_t guest_misc_enable(uint64_t val)
_ptr = (unsigned int)_ptr; \
if ( (limit) < sizeof(_x) - 1 || (eip) > (limit) - (sizeof(_x) - 1) ) \
goto fail; \
- if ( (_rc = copy_from_user(&_x, (type *)_ptr, sizeof(_x))) != 0 ) \
+ if ( (_rc = raw_copy_from_guest(&_x, (type *)_ptr, sizeof(_x))) != 0 ) \
{ \
propagate_page_fault(_ptr + sizeof(_x) - _rc, 0); \
goto skip; \
@@ -1884,7 +1898,7 @@ static int is_cpufreq_controller(struct domain *d)
#include "x86_64/mmconfig.h"
-static int emulate_privileged_op(struct cpu_user_regs *regs)
+int emulate_privileged_op(struct cpu_user_regs *regs)
{
enum x86_segment which_sel;
struct vcpu *v = current;
diff --git a/xen/include/asm-x86/processor.h b/xen/include/asm-x86/processor.h
index 5cdacc7..22a9653 100644
--- a/xen/include/asm-x86/processor.h
+++ b/xen/include/asm-x86/processor.h
@@ -566,6 +566,8 @@ void microcode_set_module(unsigned int);
int microcode_update(XEN_GUEST_HANDLE_PARAM(const_void), unsigned long len);
int microcode_resume_cpu(int cpu);
+void pv_cpuid(struct cpu_user_regs *regs);
+
#endif /* !__ASSEMBLY__ */
#endif /* __ASM_X86_PROCESSOR_H */
diff --git a/xen/include/asm-x86/traps.h b/xen/include/asm-x86/traps.h
index 82cbcee..20c9151 100644
--- a/xen/include/asm-x86/traps.h
+++ b/xen/include/asm-x86/traps.h
@@ -49,4 +49,7 @@ extern int guest_has_trap_callback(struct domain *d, uint16_t
vcpuid,
extern int send_guest_trap(struct domain *d, uint16_t vcpuid,
unsigned int trap_nr);
+int emulate_privileged_op(struct cpu_user_regs *regs);
+int emulate_forced_invalid_op(struct cpu_user_regs *regs);
+
#endif /* ASM_TRAP_H */
--
1.7.9.5
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